This bug only started a couple of months ago. I don't know if other players have seen this and I'm not sure if it's a bug even. I just need help with getting better quality.
Thanks

This isn't rlly a bug but unfortunately you don't really get a high quality picture in a 100x100 icon.
All I can suggest is this website: https://tinypng.com/

Stick your 100x100 picture in there and it'll reduce the kb on the photo and you should get a better quality. I cannot say if it will
show all the details you wish, but it's what I use!

i just do 100x100 and make it .png

100x100 is the recommended size. The maximum KB Is 512mb so you dn't need to shrink it down. There is no way that a 100x100 sized image would be larger if it's saved in .png.
Don't save in .jpg as well. The forum compresses it down by saving into .jpg, so when you upload a .jpg and it converts it into one, the quality goes down.