I tried to upload PNG image with size about 1.3 MiB, but image uploader says that an image size is more than 2 MiB:
Your image is too large to upload (over 2 MiB).
Possible explanation for this is that the image is auto-converted by imgur to JPG format. I found an unanswered question with related information: What are the factors that cause SE's Imgur instance to reduce the resolution of uploaded images?
From the user point of view it's very unclear why does uploader complain about the size of implicitly converted image rather than providing by the user.
If it's not possible to upload image "as is" in PNG format, can we just clarify the error message?