Hello, i have a question about why does scratch makes every sprite costume heavier?
Im making a 3D game, i'm almost done actually and i was just polishing some stuff and decided to make a cutscene.
Welp, got into blender, did the animations bla bla bla, went into premiere, rendered all of it as a jpeg format 20 fps just so i can get the lowest size files and also not get that many frames due to scratch limitations and yeah, 900 costumes.

All the compression i did resulted in all those images together weight about 150MB
Ok, import time, spent 9 hours importing sprites because it crashed, almost every single time, i did many things like, creating a new project, doing on the original, importing 200 frames then 200 until 900, importing directly 900, converting to gif, all resulted in crashing but finally now i got it.
On my new project i managed to get all the frames working fine etc then i exported the sprite to put in the main project and man, i was interested in how scratch managed to make a 150mb file turn into 873mb file.

Basically if you don't want to read all the text : Scratch turned my 150mb original files into a 873mb sprite file. (maybe it calculates a hitbox for each frame even if they are all a square?)
I wanted to know why does this happens, because welp, i wanted to make more cutscenes and yeah, its not even about the file size, its more about the crashing, because if the file is about 10Mb i don't think scratch will even think about dying.

So any ideas on how this works? If i get to know what makes the file heavier i can probably make a workaround for it as i did for literally my entire project.
Thanks for your time.
I don't think its necessary to link the project.

I think this is because Scratch uses a different format (PNG) to store images. It also often scales images, so they are actually larger than the imported images. I don't know any way to prevent that.

Yeah, i managed to get a fix for it even if scratch converts to png,

For the first time i rendered all my images png and it resulted in 2gb of files that i was trying to import to scratch, and for that reason it was obvious why it crashed.
But for now, i have changed my render settings do jpeg and quality to 80% and yeah, managed to get it done
So tip for any guy having trouble like i was :

Convert image to jpeg and if possible, decrease a little bit of quality, then create a new blank project just to make sure it wont crash, then import 300 images - 300 images until you reach the number that you want, of course you can do it with larger or smaller numbers but 300 was the one that didn't crash for my pc, so yeah, and if the importing rotating thingy looks like it froze and scratch freezes, just spam click on save project, like, spam for real, for some reason scratch “resets” and continues going on with the import and also now saving your project while doing so!

make sure the costume is a gif image then compres the gif file and if it is still too big then again