Is there a reason why we can upload new post icons as PNG, but not as GIF? Maybe security reasons?
I guess it's because PNG is better when you have transparency in image (in GIF you can see pixels), PNG can save more space (files are smaller) with the same or better image quality.
Few years ago PNG's were much bigger, but today the compression is very good along with the better image quality.
What they said !
PNG is just a better all around graphic format
- alpha channels = variable transparency
- cross-platform gamma and color correction
- generally compresses better than GIF (5% to 25% in typical)
You can convert GIF to PNG, you will not loose anything (nor will you really gain anything). We simply wanted to choose a single format for that location (its not a security concern) and since PNG was the more modern and in this case better format, is what we decided to use.
The only GIF support is for smileys, and that was done for the animated support (since APNG is not standard and supported everywhere)