Most of them compete with the browser UI too much and look awful on my screen.
I use a Bookmarks Toolbar and I need to be able to read that text.
I can preview, but can't use my own created images, unless I submit them to the public online gallery.
(Discussion of that here, here, and here.
This is supposed to be fixed with Firefox 3.6.7 version update.
I'll probably use Personas when the bug is fixed and I can just use my own without making them public.
It's much simpler to create them for my monitor and UI only.
My monitor is 1024x768, 17 inch.
The image sizes required for public use are much larger than what I need and only a small portion of the image is actually displayed on my screen.
How to Create Your Own Persona
"subtle, soft contrast images and gradients work best"
"highly detailed images will compete with the browser UI"
I think most people are ignoring that advice, LOL.
A person could use almost any image as long as the colors were faded with a white overlay layer on top at about 50% percent opacity.
File size limit is 300KB.
PNG or JPG file format.
Header image size: 3000x200.
Header image displays from top right to left.
I only see the top right 1024x70 (Tabs) or 1024x94 of a 3000x200 image.
If I could make headers for my use only, I could just make them 1024x100.
Footer image size: 3000x100.
Footer image displays from bottom left to right.
I only see the left bottom 1024x22 of a 3000x100 image.
When I used Edit, Find in Firefox my footer becomes about 50 pixels high.
So I'd need to make my footer about 1024x50.
I found one persona in the public gallery I really like and that's Nice Flower.
(Again, I only see the top right portion.)
Instead of using the plain green footer, I'd crop that "nice flower" header image and make a footer out of it.