ASP.NET ImageResizer not resizing GIFs and PNGs

Question

I had ImageResizer set up for years in my app and it is serving/resizing JPGs fine (I use presets) but today I wanted to resize a spacer.gif and it did not do anything. I then tried with spacer.png and it also doesn't touch it (no resize, image rendered at 1x1 pixels).

What could be going on here?

Answer 1

As covered in Basic Usage, ImageResizer does not upscale by default. You will need to specify ?scale=both&width=200 to upscale tiny images.

This is unlikely to have anything to do with the image format (namely gif/png).