Balancing size and quality of photos

by George Skarbek - 17th May 2005

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Computer Guide Q: I want to email some photos to relatives in Norway. With the old dial-up, I used to have no problems emailing two or three at a time, but since I got broadband I can hardly email one, and that takes ages. I've tried to select the folder/file/picture in My Documents, selected the file (photos), right-clicked, and selected Compress and email. I have tried both .rar and zip but each picture was still 2 MB. The instructions in Help topics also didn't work.

A: There are several ways to reduce the size of photos without a noticeable loss in quality, but using compression tools such a WinZip will not work. This is because picture formats such as JPEG or TIFF are efficiently compressed and the best WinZip or WinRar can do is to reduce them by about 3 per cent. Your choice depends on what your relatives will ultimately want to do with the images.

If they just want to view them on the screen, then, by resizing the image you should be able to reduce the 2 MB file to less than 10 per cent with no visible difference on the screen. If they want to print postcard-size prints, about an 80 per cent reduction is possible. However, if they want to print A4 or larger, only a small reduction will be possible.

Other options are to change to a more efficient format, using JPEG if you are currently using BMP, or even to JPEG 2000. Assuming you are using JPEG, you could use the compression options of the JPEG format, but probably best of all is to resize the image and then alter the JPEG compression settings.

Obtaining the balance between image quality and image size takes some practice. By increasing the JPEG compression, the file size decreases rapidly without noticeable loss until a point where some loss is visible. Many image manipulation programs allow you to view the resultant image as you test to find where that point occurs. My five-megapixel camera produced a 14 MB TIFF file that was indistinguishable from the 3.5 MB JPEG best-quality file. However, by altering the JPEG settings I reduced the file size to about a third of that. I then asked friends to view a greatly magnified section of each of the images on the screen. They could not agree which one was best. By resizing and setting the JPEG compression ratio and then viewing these images in full on a 19-inch monitor, there was no visible difference between the original and a resized and compressed JPEG image that was 58 KB, or less than 2 per cent of the 3.5 MB JPEG file.

For viewing on a screen I suggest that you resize your large image to 800 x 600 pixels and change the DPI setting to 72. However, always Save As with a different filename so that you retain the original image.

If you do not have a suitable image manipulation program that can resize images, you can download a tiny free program called Irfanview from This program can do much more, including edit the images, sharpen them, resize them, do batch conversions, view thumbnails, create slideshows that can be burned to a CD and more. It can read and write more than image 20 formats as well as a variety of movies and sound formats.


Q: I can't believe that Adobe PDF reader is still such a clumsy, clunky, slow application after all this time. Opening a document still seems to monopolise my CPU and takes far too long. Do you know of any better software or any ways of improving performance for Adobe PDF reader?

A: There is a good great free program called Foxit. This program is small and fast and does most of what the free reader can do, including having the ability to extract text from a PDF into other programs such as Word and search within the PDF file. In my opinion the displayed image is not quite as crisp as Adobe’s but is perfectly acceptable and I now use it as my default PDF reader. It runs on Windows 95/98/NT/2000/XP/2003. Foxit reader can be downloaded from:

There are several free speed-up programs that help significantly. You can download one of these from
For any readers who are using Acrobat reader version 5 and are considering upgrading, my recommendation is that there is no need. Version 5 is fast and opens all virtually all PDF files up to now. Although version 7 is faster than the previous one, the speed-up will help further.

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