Handle images that can't be resized better

[robbevp]

If the user uploads an image that cannot be resized, they don't get an error, but the image is also not returned in the serializer.

[chvp]

Do you have an example of a (valid) image that can't be resized?

[robbevp]

I don't have the image that caused this error anymore. So I don't know if it was valid (though it must have displayed on the website where I got it from).

[chvp]

I know there were a few PDFs at some point, but that doesn't make any sense to return in the image field. Unless we find a valid image that is not shown this way, I don't think we should return (a link to) it in the JSON.