Why is my explosion all squared like this?

What I did was get the Starter Content Explosion, copied it to another folder, kept only the “Fireball” and “Smoke” emitters and deleted the others. Also copied the smoke and explosion material and change those with my materials.

This is what is happening: http://imageshack.com/a/img922/9263/NKriOW.jpg

Another thing, why is this particle effect has that little red dot in it’s icon? How do I change it?

in the required node, make sure the “sub UV” tab has proper sub-image settings.
If your explosion image is a 8x8 flipbook image, your settings would look like:

that is a lit explosion keep it

Both my emitters are with the SubUV like what you are showing, but that didn’t help. I’m not using the set images from the starter content in my materials. They are different scales, could this be the problem?

Edit: I was able to make it work. Just deleted the SubUV’s and the image started working out nicely. Don’t know why it was happening though.