I try to resize any sprite, and it immediately turns purple. Also, the shrink and grow tools don't seem to be working. I've tried everything! Would somebody please help??

You would have to share the project so we could See Inside and duplicate what you are seeing.

You might have this block in one of your scripts.

change [ Sprite1] effect by (25)

Is this a vector costume with a bitmap image pasted into it? And it's the bitmap image that's turning into a purple-pink rectangle?

If so, yes, this is an occasional glitch that happens under such a situation, and I've not found a way to ‘fix’ it, apart from removing the image, and importing it back in at different sizes until you happen to find one that doesn't do it.

Do you also have text item(s) in the vector costume? (ISTR that I've seen it mostly when there's also a text item… maybe…?)

Here are some previous topics which discuss it:
https://scratch.mit.edu/discuss/topic/45960/
https://scratch.mit.edu/discuss/topic/188380/
https://scratch.mit.edu/discuss/topic/154782/
https://scratch.mit.edu/discuss/topic/187345/
https://scratch.mit.edu/discuss/topic/34763/
https://scratch.mit.edu/discuss/topic/34679/