If you are talking about the JavaScript dollmaker files, it's because it's tiny. Even if it's smooth in your art program, the image will appear pixelated because it is tiny. There are some alternatives. I have two personal favorites.
Basicbean and I made a dollmaker template for Godot which can take very high res files since Godot has it's own scaling. There is also MousePSD which works with PSD files.
I've got some more resources here too.

Probably.. I like making dress up games and I want to make more where you design yourself or another kind of girl(?).. I just didn't last jam because I found myself redrawing a lot of the stuff that was in Ophagirl, just at a higher resolution.. And it kind of bored me..
Ing eneral, I want to make more dress up games more focused on dress up aspect than anything else which would include larger games inspired by things like Style Savvy.. and probably will eventually - if I ever get more time. It's kind of an intensive style of game. I talked about Darling, Darling Sacrifices post the jam and how it's structure inspired me.. to go further.. and beyond.....
Another game I played recently also inspired me, My Paper Wardrobe. It's a tiny bit broken but still very fun. I really like fashion simulators and wish they hadn't been taken over by Roblox.
