How do i change the resolution of my screen shots that i captured from my desktop?

Question

How do i change the resolution of my screen shots that i captured from my desktop?
Thanks.

Answer 1

Do you mean you want it saved with the resolution set to something other than 72 dpi when the capture is made, or do you mean you want your capture saved at a higher resolution than the captured area?
1) If the first, there are ways to change the default capture format .png to something else, such as .jpg, .tif and a few others, but as far as I know, the resolution will always be 72 dpi. You can use Preview to change the resolution of the captured image under Tools > Adjust Size. You will get this:
If your intention is to set the resolution for professional printing defaults, then change the resolution to 300. Turn off Resample image to prevent the image from actually having more pixels added. The resolution will simply be reset from 72 to 300 dpi without changing the actual number of pixels in the image. It will also print a lot smaller since the output device will now use 300 pixels per linear inch instead of 72.
Leave Resample image on if you need to maintain the dimensions. Be aware however that scaling the image (resampling) will add a lot more pixels to the image than are there to maintain size. Expect the image to get very soft and pixelated looking when adding 417% more data to the image than it currently has.
2) If you mean you want the OS to actually save the captured area as a high resolution image at size, that can't happen. A capture is a 1:1 grab of the display buffer. It can only capture what's there. So if you capture a 700 pixel x 500 pixel area, that's all the bigger it can be without scaling it afterwards.