Be sure your vinyl is clean before applying paint by washing it with soap and water and rinsing well.
Can you paint over vinyl wall decals.
On a general note vinyl decals are rarely reusable.
If your wall decal still has problems sticking to the wall texturing you can use a paint scraper or sandpaper to smooth out the wall.
Most of the time if you remove a wall decal you will stretch the material thus decreasing the adhesion of the stretched material.
If your vinyl surface is clean the paint or primer will adhere to the vinyl rather than the dirt and you will have a longer lasting finish.
This will flatten the surface and make it easier for vinyl to stick to.
A future owner of the project might not have the same preferences as you do see the black car with pink stars above.
Prepare thoroughly or the decals will inevitably shed their new finish.
Paint will not stick to a dirty surface.
You can also use a primer between the vinyl and the paint.
Unfortunately decals are not suited for adhesion and require specific preparation before they will accept paint.
Vinyl decals can be removed relatively easily and you can change it up.
If you put it on a textured wall often it will lift paint flecks and plaster when you remove the sticker also decreasing the adhesiveness of the vinyl.
If you need to paint but are unable to remove existing decals from the surface you are working on paint over the stickers using the proper techniques.
Assuming now that you did that step before you painted and that you did the painting you can feel secure with your wall stickers being removable without bringing half of your last paint job with the adhesive on the stickers.