User:Pinsplash/Before and After Screenshots

Final result using these steps. Sure, you could upload two images separately as well, but the method I'm showing here will put them in one image, and not be too big of a file size. It will also be a little less clutter for wiki pages, and one less image that needs to be uploaded.

You can extend this to three or more images, too.

Hi! This is a quick tutorial on how I prefer to do before and after screenshots, for things like doors moving, a visual issue and the result after fixing it, how something looks in Hammer vs. ingame, etc.

My preferred image editor is paint.net. It's not overly complex for the job, like Adobe Photoshop, but is sophisticated enough, unlike say, Microsoft Paint. Also, it's free. Paint.net is what I'll be using for this. Other programs will have to follow alternate steps at some points.

1. Get your first screenshot. Most keyboards have a Prt Sc button on them. It may also say "Print Screen" or something like that. This will put everything currently on your screen into an image on your system's clipboard. You may have to hold your fn key too, if you have one. This is the fastest way to take a screenshot for Windows. Sometimes it won't work correctly, especially Goldsource games. If you need an alternative, I recommend Fraps.
2. Open a new image in paint.net and paste your screenshot in. Use Ctrl+V for quick pasting. If it asks you if you want to expand the canvas (the space used for image editing) or keep it the same size, click Expand canvas. Also, if you see any additional white space after pasting, go to Image, Crop to Selection or press Ctrl+⇧ Shift+i to get rid of it.
3. Get your second screenshot. The "after" one.
4. Add a new layer and paste your second screenshot to this one. You can open the layers window with F7 or click the small icon with the blue squares in the top right. It doesn't really make a difference which image is on which layer.
5. Shrink the image by 50%. This is optional, but it will make the image size be not so huge. Go to Image, Resize... or press Ctrl+R to bring up the resizing dialog box. Select By percentage and enter 50 for the percent. Click OK. You can also change the Resampling box which will affect the quality of the resized image. It won't make any major difference. This affects both images, by the way! You can also save this step until the very end.
6. Double the canvas size. I know, sounds a little silly after the last step, but stay with me. Go to Image, Canvas Size... or press Ctrl+⇧ Shift+R to open the canvas size dialog box. It looks and works a lot like the resizing dialog box. Select By percentage again and this time, put in 200 percent. Under the Anchor section, set this to Top Left. You can also just click the top left square. Click OK. There's a slightly different way to do this step that will let you skip step 9, just check below.
7. Move the second screenshot below the first. To select the second screenshot, go to Edit, Select All or press Ctrl+A. To move it, open the Tools window with F5 or click the small icon with the hammer in the top right, and then click on the Move Selected Pixels button (looks like a blue triangle with a plus). If it feels kind of hard to get it in the perfect spot, use the zoom buttons in the bottom right so you can get a better view.
8. Merge the layers into one. To do this, first make sure you have the top layer selected, and click the Merge Layer Down button (looks like two blue rectangles with an arrow between them).
9. Get rid of the unused white space.

1. Select the white area with the Magic Wand tool in the Tools window. Click on the white area, and all of it will be selected. It may also select some brighter portions of your screenshots. To prevent that, set the Tolerance amount to be lower. If you still can't get it quite right, use the Rectangle Select tool in the Tools window instead (looks like a blue rectangle with blue dots on the corners).
2. Go to Edit, Invert Selection or press Ctrl+i. It should now flip over to select only the screenshots.
3. Go to Image, Crop to Selection or press Ctrl+⇧ Shift+i to get rid of the unused white space.

Save it and you're done. Also consider adding numbers to your image, to show it's a sequence of events if not clear.

Step 6 Alternate Sizing

Instead of increasing the size by 200%, increase only the height. The number you want here is how tall your screen/original screenshot is in pixels. This lets you skip the lengthy process of step 9 by never creating the extra white space.