Brightness control for background images and videos

This would be extremely helpful! I often find that some images are just a little too dark on Sunday mornings and it would be great if I could adjust the brightness quickly within Proclaim.

+1 for this feature.

This would be great! I have to download, edit, and re-upload the background to accomplish this. It's tedious!

This would make my slide designs so much easier. I often want to just grab an image for a background from Unsplash or similar and dump it into Proclaim but find it's too bright to use. It's such a hassle to hack my workflow to use an external editor and try to find the right level to use.
This seems a pretty obvious feature to me and I was surprised NOT to find it when I started to use Proclaim 5 years ago. Is there any special programming support obstacle to implementing it now? 

This would be great. I've wanted to also add a blur to the image or looping video. 

Absolutely! Looping video and blur would be great, as other suggest. I also think adding a color layer would be great. Basic things you'd find in Canva or any decent editor.