Develop Reference

c# How to resize any image to specific kilobytes while retaining image type

I've seen a ton of stackoverflow articles for reducing image size, but none of them maintain the original image type (or so I've found). They usually have steps to reduce pixel dimensions, reduce image quality, and convert to a specific type of image (usually jpeg).
I have a group of images that I need to resize. They have various image types, and the filenames are all stored in a database, which makes converting from one image type to another somewhat problematic. I can't just change the filename from png to jpg because then the database won't point at a real file.
Doe anyone have an example of how to resize / reduce images to '256 kilobytes' and maintain the original image type?
For examples, here is the code I'm currently fiddling with.
public static byte[] ResizeImageFile(Image oldImage, int targetSize) // Set targetSize to 1024
{
Size newSize = CalculateDimensions(oldImage.Size, targetSize);
using (Bitmap newImage = new Bitmap(newSize.Width, newSize.Height, PixelFormat.Format24bppRgb))
{
using (Graphics canvas = Graphics.FromImage(newImage))
{
canvas.SmoothingMode = SmoothingMode.AntiAlias;
canvas.InterpolationMode = InterpolationMode.HighQualityBicubic;
canvas.PixelOffsetMode = PixelOffsetMode.HighQuality;
canvas.DrawImage(oldImage, new Rectangle(new Point(0, 0), newSize));
MemoryStream m = new MemoryStream();
newImage.Save(m, ImageFormat.Jpeg);
return m.GetBuffer();
}
}
}
Maybe there is a way I can get file fileinfo or mime type first and then switch on the .Save for the type of image?

Here is what I came up with (based on some examples that I found online that weren't 100% complete.
private void EnsureImageRequirements(string filePath)
{
try
{
if (File.Exists(filePath))
{
// If images are larger than 300 kilobytes
FileInfo fInfo = new FileInfo(filePath);
if (fInfo.Length > 300000)
{
Image oldImage = Image.FromFile(filePath);
ImageFormat originalFormat = oldImage.RawFormat;
// manipulate the image / Resize
Image tempImage = RefactorImage(oldImage, 1200); ;
// Dispose before deleting the file
oldImage.Dispose();
// Delete the existing file and copy the image to it
File.Delete(filePath);
// Ensure encoding quality is set to an acceptable level
ImageCodecInfo[] encoders = ImageCodecInfo.GetImageEncoders();
// Set encoder to fifty percent compression
EncoderParameters eps = new EncoderParameters
{
Param = { [0] = new EncoderParameter(Encoder.Quality, 50L) }
};
ImageCodecInfo ici = (from codec in encoders where codec.FormatID == originalFormat.Guid select codec).FirstOrDefault();
// Save the reformatted image and use original file format (jpeg / png / etc) and encoding
tempImage.Save(filePath, ici, eps);
// Clean up RAM
tempImage.Dispose();
}
}
}
catch (Exception ex)
{
this._logger.Error("Could not resize oversized image " + filePath, ex);
}
}
private static Image RefactorImage(Image imgToResize, int maxPixels)
{
int sourceWidth = imgToResize.Width;
int sourceHeight = imgToResize.Height;
int destWidth = sourceWidth;
int destHeight = sourceHeight;
// Resize if needed
if (sourceWidth > maxPixels || sourceHeight > maxPixels)
{
float thePercent = 0;
float thePercentW = 0;
float thePercentH = 0;
thePercentW = maxPixels / (float) sourceWidth;
thePercentH = maxPixels / (float) sourceHeight;
if (thePercentH < thePercentW)
{
thePercent = thePercentH;
}
else
{
thePercent = thePercentW;
}
destWidth = (int)(sourceWidth * thePercent);
destHeight = (int)(sourceHeight * thePercent);
}
Bitmap tmpImage = new Bitmap(destWidth, destHeight, PixelFormat.Format24bppRgb);
Graphics g = Graphics.FromImage(tmpImage);
g.InterpolationMode = InterpolationMode.HighQualityBilinear;
g.DrawImage(imgToResize, 0, 0, destWidth, destHeight);
g.Dispose();
return tmpImage;
}

In .Net, while converting "Image" with another image , then one of the image's color quality is affected

In .net application when the image is processed & merged with another image then its colours are affected.
Image image ---------> Uploaded image
Bitmap xy = new Bitmap(image, image.Width, image.Height); -----> Conversion into Bitmap to perform various operations like resize or merge with another image.
So the “image” object has few “PropertyItems” and when we convert image to Bitmap type of object then these “PropertyItems” array is empty, which means these “PropertyItems” were not moved in this conversion.
Now after this image is moved into Bitmap object for merging with another image, then “PropertyItems” array is empty
Due to loss of these propertyitems, color of the image is changed.
For merging, I'm using below code
public string MergeImages(List<BlockPositionDetailsWithSize> blockPositionDetailsWithSize, int layoutWidth, int layoutHeight)
{
var bitmap = new Bitmap(layoutWidth-75, layoutHeight);
float width = 0, height = 0;
using (var g = Graphics.FromImage(bitmap))
{
g.InterpolationMode = InterpolationMode.HighQualityBicubic;
g.SmoothingMode = SmoothingMode.HighQuality;
g.PixelOffsetMode = PixelOffsetMode.HighQuality;
g.CompositingQuality = CompositingQuality.HighQuality;
var bitmapImg = blockPositionDetailsWithSize.Where(b => b.BlockId.Contains("fImageBlock")).FirstOrDefault();
// This loop is placing two images in graphic object
foreach (var block in blockPositionDetailsWithSize)
{
width = block.Width;
height = block.Height;
g.DrawImage(block.BlockImage, block.PosX, block.PosY, block.Width, block.Height);
}
}
ImageCodecInfo jpgEncoder = GetEncoder(ImageFormat.Jpeg); // change image format
System.IO.MemoryStream ms = new System.IO.MemoryStream();
bitmap.SetResolution(288, 288);
System.Drawing.Imaging.Encoder imgEncoder = System.Drawing.Imaging.Encoder.Quality;
EncoderParameters imgEncoderParameters = new EncoderParameters(1);
EncoderParameter imgEncoderParameter = new EncoderParameter(imgEncoder, 95L); //A quality level of 0 corresponds to the greatest compression, and a quality level of 100 corresponds to the least compression.
imgEncoderParameters.Param[0] = imgEncoderParameter;
bitmap.Save(ms, jpgEncoder, imgEncoderParameters);
byte[] byteImage = ms.ToArray();
string base64String = string.Empty;
base64String = Convert.ToBase64String(byteImage); ////Get Base64
return base64String;
}
Image's color quality can be maintained by following code
foreach (System.Drawing.Imaging.PropertyItem item in bitmapImg.BlockImage.PropertyItems)
{
try
{
bitmap.SetPropertyItem(item);
}
catch
{
}
}
Now the issue is I cannot apply one image's property item on the final image(produced after merging). Because when I apply one image's property items onto another image then the second image's color quality is affected but if I don't apply then the first Image's color quality is affected.
So I am looking for the way to merge two images without loosing of any it's property items.

C# Crop & resize large images

I got some very large building drawings, sometimes 22466x3999 with a bit depth of 24, or even larger.
I need to be able to resize these to smaller versions, and to be able to cut out sections of the image to smaller images.
I have been using the following code to resize the images, which I found here:
public static void ResizeImage(string OriginalFile, string NewFile, int NewWidth, int MaxHeight, bool OnlyResizeIfWider)
{
System.Drawing.Image FullsizeImage = System.Drawing.Image.FromFile(OriginalFile);
if (OnlyResizeIfWider)
{
if (FullsizeImage.Width <= NewWidth)
{
NewWidth = FullsizeImage.Width;
}
}
int NewHeight = FullsizeImage.Height * NewWidth / FullsizeImage.Width;
if (NewHeight > MaxHeight)
{
NewWidth = FullsizeImage.Width * MaxHeight / FullsizeImage.Height;
NewHeight = MaxHeight;
}
System.Drawing.Image NewImage = FullsizeImage.GetThumbnailImage(NewWidth, NewHeight, null, IntPtr.Zero);
FullsizeImage.Dispose();
NewImage.Save(NewFile);
}
And this code to crop the images:
public static MemoryStream CropToStream(string path, int x, int y, int width, int height)
{
if (string.IsNullOrWhiteSpace(path)) return null;
Rectangle fromRectangle = new Rectangle(x, y, width, height);
using (Image image = Image.FromFile(path, true))
{
Bitmap target = new Bitmap(fromRectangle.Width, fromRectangle.Height);
using (Graphics g = Graphics.FromImage(target))
{
Rectangle croppedImageDimentions = new Rectangle(0, 0, target.Width, target.Height);
g.DrawImage(image, croppedImageDimentions, fromRectangle, GraphicsUnit.Pixel);
}
MemoryStream stream = new MemoryStream();
target.Save(stream, image.RawFormat);
stream.Position = 0;
return stream;
}
}
My problem is that i get a Sytem.OutOfMemoryException when I try to resize the image, and that's because I can't load the full image in to FullsizeImage.
So what I would like to know, how do I resize an image without loading the entire image into memory?

There are chances the OutOfMemoryException is not because of the size of the images, but because you don't dispose all the disposables classes correctly :
Bitmap target
MemoryStream stream
System.Drawing.Image NewImage
are not disposed as they should. You should add a using() statement around them.
If you really encounter this error with just one image, then you should consider switch your project to x64. A 22466x3999 picture means 225Mb in memory, I think it shouldn't be an issue for x86. (so try to dispose your objects first).
Last but not least, Magick.Net is very efficient about resizing / cropping large pictures.

You can also force .Net to read the image directly from disk and stop memory caching.
Use
sourceBitmap = (Bitmap)Image.FromStream(sourceFileStream, false, false);
Instead of
...System.Drawing.Image.FromFile(OriginalFile);
see https://stackoverflow.com/a/47424918/887092

How compress image without change the original height ,width of image in c#

I want to make image size smaller then its original size.I am using following code for compress the size images but it increased the image size from 1MB to 1.5MB
Any Other solution for compress large size images without change image original height,width.
public static byte[] CompressImage(Image img) {
int originalwidth = img.Width, originalheight = img.Height;
Bitmap bmpimage = new Bitmap(originalwidth, originalheight);
Graphics gf = Graphics.FromImage(bmpimage);
gf.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
gf.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.AssumeLinear;
gf.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.NearestNeighbor;
Rectangle rect = new Rectangle(0, 0, originalwidth, originalheight);
gf.DrawImage(img, rect, 0, 0, originalwidth, originalheight, GraphicsUnit.Pixel);
byte[] imagearray;
using (MemoryStream ms = new MemoryStream())
{
bmpimage.Save(ms, ImageFormat.Jpeg);
imagearray= ms.ToArray();
}
return imagearray;
}

You can set the quality level when you save the file as JPEG, which mostly also directly will correlate with file size - the less quality the smaller your output file will be.
Also see How to: Set JPEG Compression Level , for an example see this SO answer.

As said by #BrokenGlass you can specify the compression level within the EncoderParameter. Here's a snippet if you want to give a try changing quality:
public static void SaveJpeg(string path, Image image, int quality)
{
//ensure the quality is within the correct range
if ((quality < 0) || (quality > 100))
{
//create the error message
string error = string.Format("Jpeg image quality must be between 0 and 100, with 100 being the highest quality. A value of {0} was specified.", quality);
//throw a helpful exception
throw new ArgumentOutOfRangeException(error);
}
//create an encoder parameter for the image quality
EncoderParameter qualityParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality);
//get the jpeg codec
ImageCodecInfo jpegCodec = GetEncoderInfo("image/jpeg");
//create a collection of all parameters that we will pass to the encoder
EncoderParameters encoderParams = new EncoderParameters(1);
//set the quality parameter for the codec
encoderParams.Param[0] = qualityParam;
//save the image using the codec and the parameters
image.Save(path, jpegCodec, encoderParams);
}

Making image thumbnail smaller

I am having image sharing application where users upload images and I take thumbnails of these images...how ever , everything is working fine but sometimes the image thumbnail(600 * 800) size is almost 1 mb which is very huge is there anyway to modify the image resolution or something to make the size like..100 kb or something . this is my code .
Bitmap bmp = new Bitmap(Width, Height);
System.Drawing.Graphics gr = System.Drawing.Graphics.FromImage(bmp);
gr.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
gr.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
gr.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
gr.PixelOffsetMode = PixelOffsetMode.HighQuality;
System.Drawing.Rectangle rectDestination = new System.Drawing.Rectangle(0, 0, Width, Height);
System.Drawing.Size rs = new System.Drawing.Size();
rs.Height = Height;
rs.Width = Width;
gr.DrawImage(originalImage, new Rectangle(new Point(0, 0), rs), 0, 0, originalImage.Width, originalImage.Height, GraphicsUnit.Pixel);
string thumbnailPath = string.Concat(pathToSaveIn, thumbnailName);
bmp.Save(thumbnailPath);
gr.Dispose();

The image resizing code looks OK (at first glance). However, you're saving the image in bitmap format, which is lossless -- hence the large size of the file.
You probably want to use JPEG instead for a thumbnail: for photographs, etc., this gives good compression.
This may help:
public void SaveImage(Bitmap image, string filename)
{
long quality = 80L; // adjust as appropriate
var qualityEncoder = Encoder.Quality;
using (var encoderParameter = new EncoderParameter(qualityEncoder, quality))
using (var encoderParams = new EncoderParameters(1))
{
encoderParams.Param[0] = encoderParameter;
var jpegEncoder = GetEncoder(ImageFormat.Jpeg);
image.Save(filename, jpegEncoder, encoderParams);
}
}
private static ImageCodecInfo GetEncoder(ImageFormat format)
{
ImageCodecInfo[] codecs = ImageCodecInfo.GetImageDecoders();
return codecs
.Where(codec => codec.FormatID == format.Guid)
.FirstOrDefault();
}

This looks like .NET. Scott Hanselman had a good blog post on this. Essentially a review of a package on NuGet that helps with this.
http://www.hanselman.com/blog/NuGetPackageOfWeek11ImageResizerEnablesCleanClearImageResizingInASPNET.aspx

Try System.Drawing.Image.GetThumbnailImage. I haven't used it myself, but looks like it might work.