How to change the resolution of a picture?

I have taken a picture with my digital camera and now I want to make it in to a 8x10 and 5x7's. I uploaded my picture to GIMP and did what I wanted. Then I had the picture printed and I used one of those scanner things at walmart and made an 8x10. Looked like crap! How do you take a digital size picture and make it larger without it looking blurry and grainy? Like I said I use the GIMP program but i am very new so I will need help! Thank you!How to change the resolution of a picture?
Did the Walmart scanner have settings on it? I don't use those, so I'm not sure. If it did, it should have about three choices with dpi. You should always choose 300. The image will scan in much clearer.



I'm not sure about GIMP, but if you have photoshop, you can change the resolution also with the image size menu to a larger amount, it'll help, but probably not as much. How to change the resolution of a picture?
My fear is that 1) you have not been shooting using your cameras highest resolution. 2) when you did all your adjustments on your images, you overwrote your original image file ... always save changes as a different file name. 3) once you reduce the size of an image file, you cannot ever make them larger without pixelation.



Seeing your image on your computers monitor at 72 DPI vs. a photo print at 300 DPI may well be the difference you are seeing.



Make sure you have your camera set to use its highest resolution and then try again.
Once you've taken the picture, you can't improve the resolution. You need to change a setting on the camera itself.
it's true, once the image is taken, the resolution can not be increased.