I make pixel art mspaint and would like to paste some I've already made into aesprite. But I'm running into a few problems

I’m not able to make my images transparent unless they’re indexed but when I make a new background as indexed it really messes up the colors and I lose a lot of what my art looked like. Is there any way to resolve this? It’s very frustrating.

Save the Paint image in PNG format, open it on windows image view and use the right mouse button to copy
go to aseprite and click new RGBA file and it will be already in the right image size you copied, the new file will be a transparent image. press ctrl+v now you can make transparent areas deleting the colors you wish to be transparent on aseprite.
To delet all not connected of same color use it in the magic wand tool

Thank you so much you’re awesome jamesfoxbr

I didn’t want to make another topic for this but I have another question. I’ve been trying to reduce the amount of different shades I’ve been using but when I create a palette in aesprite I notice there are many similar colors. This is from when I made something in MSpaint, is there any way to change colors on the fly easily in the palette to reduce the amount of different colors showing up? For example if I have 4 different shades of purple in the palette but they look very similar is there any way to just take one shade of purple from the palette and change the other 4 boxes to that shade and it would reflect the change where those colors are on the sprite?

Use the Paint Bucket Tool with Contiguous unchecked and a Tolerance above 0 to replace similar colours with a single colour of your choice. To then set your palette to only those colours left in the image, click the menu button on the palette, and then Create Palette from Current Sprite.

If you want to work with the palette, then go into RGB mode (so changes to the palette don’t mess up the image), delete any redundant colours in your palette (select the swatch and press Backspace or Del), and then convert to Indexed mode. Aseprite will automatically match non-existing colours in the image to the closest colours in your newly reduced palette.

Thank you so much everyone for the help. I have another question. I’d like to animate one character I’m making but I’d also like to animate small things around them which would be part of their character but. Is it possible to add or draw on top of an existing image and then animate the small things without altering the character?

Example, if I want a character who normally has a pose and I want lets say meteorites flying around them, is there a way to do this without having to redraw part of the character when I move those meteorites around?

You could have the character on a continuous layer with the cells all linked (so it’s just one cel shared across all frames), and animate the meteorites on different layers.

Is that on each new frame where it would say
1|2|3
o|o|o

Or do you mean where it would say
Layer 2
Layer 1

I’m not sure how to edit layer 2 when I try that with an image

Each new frame is those numbers, the first thing you posted. The second thing is layers.

What do you mean by “not sure how to edit layer 2”? select a cel (those circly bits) on layer 2 and edit it.

That makes more sense now thank you. I figured it out now, sorry about that. Thanks for being patient.