JPEGs (or JPGs) are one of the preferred file formats and extensions for digital photos and high-resolution images, because the JPEG format compresses the image data while retaining a high level of sharpness and clarity. However, even with the JPEG format's native compression, photos and images can be saved in file sizes too large to be easily uploaded to and downloaded from photo-sharing sites or Web pages. In this case, you can manually edit the photo or image in photo-editing software to save it in a lesser-quality range, reducing the total size of the file.
Open your photo-editing program, and open the photo or image you want to edit.
Crop any unnecessary background using the program's cropping tool.
Remove any watermarks from the photo or image. Watermarks can dramatically increase a JPEG's file size.
Resize the image to a smaller size by clicking "Image Size" or "Resize," depending on your program. Click the box that constrains the JPEG's proportions; otherwise you will distort the image.
Use your program's "Optimize for Web" settings, if it has these preset. These settings will automatically adjust the resolution and colours to reduce the file size.
Click "Save As" and lower the photo's quality rating to reduce the file size even more. For example, in Photoshop CS4, there is a slider bar that appears after you click "Save As." Sliding the bar to the right reduces the image's quality.
Always keep a copy of the original JPEG at its former size, just in case. Once you have reduced a file size and JPEG quality, you cannot undo the changes.