Only if they need enlarging mate.
I like to make them big, usually 1200 pixels wide, but only if they stay crisp.
A lot of pics go grainy if you try to enlarge them too much, in which case you have to make them smaller, such as 800/900/1000 or 1100.
I do the re-sizing in Irfanview BEFORE putting them into Photobucket, and also lighten/darken/sharpen them at the same time.
To draw arrows and stuff on the pic, or type words on it, I then use Paint.
Only when all that is finally done, I upload it to Photobucket.
When it's in Photobucket, i never touch it again.