Resizing images

This is a subject often asked, but obviously not asked often enough.  Today’s 12 megapixel cameras output images which are roughly 4200x3400 pixels and in jpeg format roughly 3mb in size.  Have you ever seen your mailbox icon flashing for what seems like forever and no mail coming through?  Chances are someone sent you a bunch of their latest vacation photographs and didn’t resize them, and now you’ll have to wait as your mail server processes 30-40mb’s of images.  Wouldn’t it be nicer if the images were only 40-60kb’s and you could view them just fine?   I’ll show you how.

The most common computer monitor used today has 1024x768 pixels of resolution.  This is on the cheaper end of monitors.  Each pixel represents a tiny individual light that can be any color.  No matter what you do, how big the image is, you can only view 1024x768 (or 786,432) pixels at any one time, and that’s only if the picture perfectly fits your screen.  This is more than four times less than the original files!  If you resized your image to 1024x768 you would not see any more detail, no better picture, nothing better at all, over viewing the original file ‘full size’ on the same monitor.  The ONLY benefit to a full size image, is that you can zoom in on parts of it and see more detail.   If a 1024x768 image filled your screen and you zoomed in, it would zoom in, but it would start pixelating (where you can see the individual pixels of the image) right away.   A full size image would allow the viewer to zoom in and read license plate numbers.

Do the people you send your photos to need to read license plate numbers?  I doubt it.  The largest image used in this column is 600 pixels wide at the longest point and the file is 69kb vs. the original 3.4mb’s.  In other words, it takes just a second to pop up on your screen, where a full size image would take minutes.   It works the same way with email.  Most images are meant to be viewed in “full frame” (where you see the entire picture at once) and are fine for sharing holiday pictures and the such with friends and family.  When I email my friends and family I send them 600 pixel images on the longest side, and tell them if they want bigger ones to make a big print from to just let me know and I can send it separately.   Keep in mind, that if a 600 pixel image fills a physical area on your monitor of say 5x7 inches, then that 600 pixel image will make a perfectly good 5x7 photograph.

How do you resize?  Windows Vista’s Photo gallery has an “email” tab.  Bring your image up in the viewer and click “email” and it offers you some choices of resolution and as you choose the different resolutions it estimates the size of the final jpeg file.  A 640x480 resolution image makes a roughly 50kb file and will send very fast via email, view a nice large size, and even make nice 5x7 prints.  Overkill not desired.  Once you choose your resolution the Photo Gallery asks if you want to attach it to an email or save it in a separate directly to attach yourself.  Choose which is most convenient and that’s all there is to it.

What if you don’t have Windows Vista?  Every operating system comes with a picture viewing program and a paint program of some type.  Open the picture in whatever photo software you have, go to image resizing, and put in your desired resolution.  Then go to “file” and “save as” and when saving a jpeg is then asks you which compression you want.  Choose 50-70% compression.  The image will look fine.  At this size compression artifacts won’t be an issue.   I hope you found this topic useful and will soon be sharing your photos with family and friends.