Knowing how to resize digital photos can reduce file size without sacrificing quality.
Photographers who know how to resize digital photos are able to reduce the file size, maintain the image quality and use the photos in a variety of computer and Web applications. It is important to save the resized photo as a copy to preserve the original, especially when cropping out a portion of the photo. Photo resizing programs allow the user to constrain proportions when resizing, which means the photo's appearance remains the same even when the size changes. Once resized, the photo can be shared, inserted into a computer application or printed to fit a certain size of frame.
Reducing the file size is crucial when sending photos via e-mail or using computer applications that benefit from a small file size. Photos from a typical digital camera are about 3 megabytes. While this may be suitable for storing the pictures on a hard drive, transferring 3-megabyte files via e-mail or sharing them on the Web is not recommended. Files this large download slowly and are sometimes rejected altogether by photo sharing sites and mail servers.
A second advantage in photo resizing is the ability to adjust the on-screen display size of the photo. Digital photos are made up of pixels, which are tiny dots of color. Pixels are expressed by a measurement such as 1200 X 900. The first number is the number of horizontal pixels and the second is the number of vertical pixels. The pixels represent the length and width of the photo. More pixels allow a photo to be enlarged and still retain a high-quality image on screen and when printed.
There are many programs that can resize digital photos, and they range from expensive to free and from easy-to-use, single-purpose applications to complicated photo editing suites. As long as the program reduces the pixels of the photo, allows for constraining proportions and allows the user to manually input a desired size, the program will get the job done.
Adobe Photoshop is a high-end solution for professionals who need photo editing features beyond photo resizing. In June 2008, CNET ranked Adobe Photoshop as one of the top five applications. One advantage of using Adobe Photoshop to resize photos is the ability to easily alter photos to any aspect ratio. Most digital cameras capture pictures with a 4:3 aspect ratio, but most standard picture frames have different aspect ratios: 2:3 for a 4-by-6-inch photo, 5:7 for a 5-by-7-inch photo and 4:5 for an 8-by-10-inch photo. By choosing the crop command from the Image menu, an Adobe Photoshop user can instantly crop a photo to any aspect ratio. Adobe Photoshop costs from several hundred dollars to nearly $1,000. According to PC Magazine, Adobe Photoshop Elements 6 is an affordable photo editing tool for amateurs.
A simpler program included with most versions of Microsoft Office, Microsoft Picture Manager, also provides photo resizing functionality as well as basic photo editing. The program allows users to manually input the number of pixels to resize a photo, but also offers a compression feature that automatically resizes photos down to the appropriate size for documents, websites and e-mail.
An even simpler and free option is Photo Gadget. With a Photo Gadget, a user can resize any photo simply by right clicking on it, selecting resize and choosing a size.
Photos can also be resized without using a program at all. Resizr.com allows users to upload any photo to the site, manually input what size they want the photo and download the resized picture to their hard drive.
Because large photos download slowly and take up too much of the screen, it is desirable to shrink photos considerably before uploading them to the Internet. Photos on the Internet should be reduced to a size of 640 X 480. This allows the photo to be big enough to be seen without squinting, but also makes the photo small enough to not dominate the entire screen.
Photos uploaded to the Internet can also be compressed, which reduces their file size and allows them to download much faster. This is done by reducing the quality of the photo, but not usually enough to be noticeable in a small photo displayed on a computer monitor. Compression can be done automatically using the website compression setting of Microsoft Picture Manager, or by adjusting the quality slider when saving a photo in Adobe Photoshop. An ideal file size of a photo on the Internet is about 100 kilobytes.
The number of pixels a digital photo has can affect the quality of a digital print. More pixels than necessary will not improve the quality of the print, but too few will result in a blurry photo. Therefore, a photo with more pixels can be made into a larger print. The minimum size of a photo for professional-quality prints should be 350 X 540 for a 4-by-6-inch photo, 450 X 630 for a 5-by-7-inch photo and 1200 X 1500 for an 8-by-10-inch photo.