Bitmap PNG transparency not placing/ dragging into Illustrator.

Hi,

I have a texture pack I've used for years. It has black print textures on transparent backgrounds in a .PNG format. I've always been able to place them in my Illustrator files and recolour the black areas very easily using swatches.

I haven't used these in a while, today when I tried it out I could still recolour the black areas but the transparent area shows as white and I can't figure out how to get rid of it.

If it helps the files should work like they do in this video at the 50 minute mark https://www.youtube.com/watch?v=pt8qS5jyDu0&t=3112s

I made my own textures using this technique a while back and those files don't work either.

Has something changed with the programme? Is it me? I factory reset my laptop a few months ago so it could have been a change in preferences.

Any help appreciated.