There are many reasons why an image may look fuzzy or blurry. In some cases, a blur may occur during the picture taking process, but often, the culprit is image resolution or problems with image quality. Problems with image quality can be fixed easily.
According to the National Park Service's promotions office, DPI or image resolution refers to "dots of ink and spaces between the dots that [print onto a piece of] paper." Together these dots form an image. The more dots, the crisper the image. Programs like Photoshop allow users to increase the number of dots within a picture, thus increasing the size of the image. Unfortunately, the program can only guess where the dots need to go, and sometimes it redistributes them in a way that results in a fuzzy or blurry image. In most cases, the image looks blurry because it was increased beyond 25 percent of its original size.
According to Photoshopessential.com, "it's usually okay to make your image smaller without losing much in the way of image quality…[but] you will absolutely lose image quality if you try to make your image larger." If you've over-enlarged an image, you will need to either adjust the image resolution or apply a sharpening mask to make the image crisp and clear.
Sharpening The Image
Launch Adobe Photoshop and open the file you want to manipulate. Go to the File drop down menu and select "Open." Browse through the file directory and select the file you want to adjust.
Adjust the image resolution. Photos look best printed at 300 DPI. A DPI under 300 will look fine on a computer screen, but will be blurry when printed. To adjust DPI, go to the Image drop down menu and select "Image Size." Make sure the "Constrain Proportions" box is checked and adjust the resolution to 300 pixels. This will redistribute the DPI, resulting in a smaller, but clearer photograph.
Sharpen the image if adjusting the resolution doesn't achieve the desired result. Right-click the background layer to duplicate it. Name the new layer "sharpen." The easiest way to sharpen is to use the Sharpen tool. The Sharpen tool is located in the toolbox to the left of the design space. In most cases, you don't need to sharpen the entire photo, just certain sections. You can use the Magic Wand tool and the Smart Selection tool to highlight areas you want to sharpen. Make sure you have the "sharpen" layer selected in the layer palette and use the Rectangular Marquee tool or the other tools listed above to highlight the photo's main content. With the area you want to sharpen selected, apply the effect. Select the Sharpen tool from the toolbox and adjust the size and strength of the brush. Use the master diameter slider located at the top of the page to make the brush larger or smaller. You will need to adjust the size of the brush to fit your selected space. Set the strength of the brush to 25 percent for good results. Once you've adjusted the brush settings, click the brush over the selection to bring the content into better focus. The Sharpen tool will only effect the area of the image that has been selected with a selection tool.
Save your image using the "Save As" method, otherwise you will permanently alter the size of your original image. Go to the File drop down menu and select "Save As." Save the image as a JPEG file for maximum compatibility between computers.