[shedrock]

Here are the ones I did so far.

Excellent, the transitions are very good!
If the pictures get a little more sharp, it's perfect. If I remember correctly you use GIMP. I am convinced that the blur is not at the source you are using, more the editing in GIMP. I had the same problem editing images when scaling or save, the sharpness in contrast to the original get lose when i played around with GIMP for fanart.tv. I think that cause was in GIMP on scaling -> try other interpolation settings (i think that was the cause of sharpness/quality loss. Can also be that I am wrong, it's pure from my memory.) 

I actually never used GIMP. Graphics are definitely not my thing.

Anyway, I only used the Remove BG site and then touched up with Adobe PS. It's weird because I am not seeing the quality loss on my end.