I am new to the whole screensaver creation thing and new to Gimp. I seem to be having trouble getting the screensaver to save at 600 x 800. When I go to image, scaling and put either 600 or 800 in the boxes for w and h it changes both numbers. How do I get them both to be correct at the same time? And even if I use the rectangle selection tool to crop to a rectangle my numbers seem to never stay at either 600 or 800 when saved. I usually end up with 573 or something instead of the 600. Any help with this will be appreciated.
Normally you want the height and width to stay "locked" so that the image proportions (a.k.a. aspect ratio) do not change. What I try to do is scale the image so that I have the 800 height or 600 width (depending on the proportions so that the other dimension is larger than needed), then use the rectangle select and cropping tools to get rid of the excess width/height (e.g. if you scaled it to 630 x 800, then you would select an area 600 x 800 from that resized image and crop it so that you have the 600 x 800 size.
One "gotcha", when using the rectangle select tool, make sure that "feathering" is unchecked, as that can cause you to select a larger area than you meant (with the excess being for the feathering effect).
Also is there someplace that shows samples of the different text fonts in Gimp or do you have to go through them one click at a time?
Not within GIMP itself, that I know of, but if you go to the fonts directory on you computer you can double-click a font file to view a sample (at least in Windoze, anyway). On Windoze 7 go to Control Panel -> Appearance and Personalization -> Fonts. GIMP also has a directory where you can download font files just for it, which will be something like "C:\Program Files\GIMP-2.0\etc\fonts".