Pixelated images can be annoying and make what should be a beautiful scene into one that is painful to look at. Pixelation is a result of poor initial image quality, expanding an image too much or compressing an image then expanding it. Because pixelation represents the limit of information available in the image, it is impossible to generate a perfect image from a pixelated one, but with an image editing program it is possible to make the image look better.
Use a blur filter to smooth out harsh or jagged edges that result from pixilation. These filters will take the image, and, by averaging the colours, smooth out all the harsh edges. While Gaussian Blur filters are recommended, the best filter varies based on the type and quality of image you are using, as well as the lighting of the image. You might want to try other filters. Set the blur filter to a setting of two or three pixels, or the image will not be altered at all. Experiment with various settings of the filter, increasing the width if your image is still too jagged after applying the filter. Apply the blur filter multiple times if you think your image requires it.
Apply a sharpen filter to fix any excessive blurriness that results from blur filters. After applying the blur filter multiple times to get rid of the pixelation, you might find that the image is too smoothed to make out anything. In this case, try applying the sharpen filter. With this filter, the program will attempt to sharpen the edges in the picture and make the subjects clearer. Experiment with this filter and various settings, and you might be able to produce an image that you like. Be careful because too much sharpening can make an image look harsh.
Use more artistic filters to find another solution. Filters such as the cutout filter can turn a painfully pixelated image into a smooth and artistic one. If you do not care about the image looking particularly sharp or realistic, try playing around with some of the artistic filters.
Some images just cannot be saved, no matter what you do to them. If you've been trying for hours without producing something pleasant to look at, it might be time to give up. While professional photo editing programs such as Photoshop do provide a user with more tools, most programs can blur and sharpen an image enough to be useful.
Save a backup copy of the original image in case you don't like some changes you make.