The tutorial
For this entire tutorial, for all images make sure that the background color in paint is the color of whatever brush/texter/gradient/whatever and that transparency is on. You can change the background color in paint by left clicking on the color you want to be the background color
First open your image. One of the 800x600 neopets backgrounds would work nicely. Crop the background to approxamately 600x600 pixels. A little bigger or smaller doesn't really matter though. Click on any tool, then click on the rectangular selection tool. At the top, go to image -- stretch/skew (or ctrl+w). Stretch the image 200% both horizontally and vertically. On the you page, under For Ms Paint Users, click brushes (2) or textures. Copy and paste some brushes and/or textures on your image. Use a decent amount, but don't overdo it. Then click any different tool, and click back on the rectangualr selection tool. You do this to get rid of any selection that you might currently have. Then go back to stretch/skew (or ctrl+w) and stretch the image (both horizontally and vertically) 50%. Then go back to stretch skew (or ctrl+w) and stretch your image to 200% again. Paste on a gradient. Then click a different tool, and click back on the rectangular selection tool to get rid of the selection. Shrink the image to 50%, then stretch the image to 200%. Paste on some more brushes. Continue shrinking and stretching the image as you see fit. Shrinking and stretching makes the edges on things smoother and makes gradients, some brushes, and transparent blogs not look like little dots. Too much shrinking and stretching can make the image pixelly however, so don't do it too much. When you are satisfied with how your layout looks and your layout is normal sized, stretch it to 200% paste on a transparent blog, then undo the selection, stretch your image to 50%. Paste on a shaping/border. Crop your image as you see fit, then save as a .png. Your finished =)
This is what I ended up with:
