How do I maximize the resolution of screenshot images?
The number one way to ensure good image and screenshot resolution is to save images that are scaled to the proper size - in other words, adjust the height/width of your image *before* uploading it to the web.
- Screencapture software like Jing (free) or Snagit (not free) will give you the option to do this as you're capturing the image through the "Resize Image" option.
- If you're using the "Print Screen" function on your computer to capture images, you can open up those image files in your computer's native image previewer (Microsoft Photo Manager, Mac's Preview, etc.) and use the "resize image" or "adjust image size" option.
- There's also software you can download that will help automate the process - here's a site I just found: http://toki-woki.net/p/Shrink-O-Matic/
To know what size your image should be, just figure out the width of the column you want to use by going to "Add/Edit Pages" --> "Resize Columns". You'll want to subtract about 10 pixels from the column size to account for box borders and padding.
If you absolutely need to adjust image size using the html options in the image manager, the best advice I can offer is to make sure that the height and width of your original image, when calculated in pixels, end in even numbers.
As an example, resizing an image that's 620x420 pixels will work much better than resizing an image that's 621x427 pixels - in the latter example, since the numbers aren't evenly divisible, a web browser trying to display the image has to split the difference - the math just doesn't work as nicely. :)