Hi rusecure,
I've emailed you privately, but I'll repeat it here.
I use the Gimp 2.6. The trick is to do the following:
If you can, crop the excess background from the picture. Do this by
1. opening the toolbox - go Tools/Toolbox (or Cntrl + B).
2. Click on the rectangle in the top left hand corner of the box, which is your rectangular selection tool.
3. Click, hold and drag a box over the relevant areas.
4. Go Image/Crop to selection.
I've used this method to crop to Diana's face to show the detail.
Okay, after this, you scale the image so that the longest side is 600 pixels.
1. Go Image/Scale Image...
2. Change the largest side to 600. Don't click on the little chain icon, since it maintains the proportions. If you click on that, you unlink the two dimension and will end up with one dimension scaled only and a distorted picture.
3. Click on 'Scale'.
The final compression happens when you save.
1. Go File/Save as.
2. chose a new name
3. click Save
You will now see the box titled 'Save as JPEG'. At the top of the box is a drag bar labeled "Quality". Click on this bar and drag it back to about 90. this should compress the JPEG enough to fit the board.
You can play around a bit - slightly larger pictures (up to 800 pixels) will fit if the quality is even less, but you might lose detail.
Most other graphics manipulation programs will compress JPEGs during the save operation. Be aware though that every time the JPEG is resaved and compressed that it will lose quality. This can be fine on the web, but disasterous if you're wanting to print!
I also like to sharpen (filters/enhance/sharpen) and up the contrast a bit (colors/brightness and contrast), especially on clear glass where it can be hard to see the detail. mind you, that looks okay on my laptop and I have no idea what it looks like on other monitors.
Some others are far better with image manipulation, so they might correct me!
Hope that helps.