Making a decent screenshot is very important,if you want to show the quality of your theme work.

So here is how.................

SE theme creator (XP users) - Open the preview window,and press alt + PrtScn (print screen) on your keyboard user posted image
This will copy the "active" window image to the clipboard,then open your paint program and "paste" as new image. You can now crop individual screens to the correct upload size.

Nokia Theme Studio s60 and s40 (s60 all versions from 1.14) - Open the theme studio preview screen,and double click the screenshot you want,then select 'send to local storage device'
user posted image
This will save a high quality 176x208 .jpeg to your chosen hard drive location.

If you want an 'actual' screenshot from your phone,download FExplorer,install on your phone,and look through the options to check the key combination (usually 'pencil' and 'joystick in'),keep FExplorer running in the background by pressing the Red (end call) key,and then press the key combination.