System.OutOfMemoryException when loading multiple large images from disk

Question

I try to load images from disk (sizes of 30 to 50 MB each) in a list as follows

    var images = new List<Image>();
    foreach (var imgPath in paths)
    {
        var img = Image.FromFile(imgPath);
        images.Add(img);
    }

The problem is that after the first or second image I get a

System.OutOfMemoryException

...my guess is that the images are too large. I know that a good practice would be to process the images one by one, but I can't since I need all of them to be merged into a single one (like a collage) and I can't use thumbnails because I need to respect the original sizes.

I tried to change the maxRequestLength to "10000000" but it was useless.

Since I can't reach the image processing step I don't think that I have a problem with not disposing objects, at least not yet.

Is there a way to increase the memory available to work with, or something like that?

PS I use JPG format for images.

Answer 1

I don't recommend using:

Image.FromFile(path);

It's slow and will bloat your process Instead:

var fs = new FileStream(path, FileMode.Open, FileAccess.Read);
var photo = Image.FromStream(fs, true, false);

Don't forget to dispose ;-)

Basically instead of bringing all that data into memory in one go and killing your app and all your loved ones. You operate the image as if it was a stream of data.

Edit

In either case I don't recommend editing all the images at once. You'll probably get a OutOfMemoryException either way.

If possible work with two images at the time, once you're done, dispose them and move to the next set until your final image is complete.