Here's our picture open in Graphic Converter. This used to be bundled with most Macs but is now a $30 shareware application. If you need to resize pictures or convert format a lot then Graphic Converter may suit you very well. It also ha some very advanced editing features - some people find they don't need another editing application.
Resizing is very easy. Just select Picture…Size…Scale and you will get the following screen.
(If you're not familiar with this notation “picture…size…scale” means “go into the picture menu and select the size option then choose scale from the flyout”). Here's a close up of the panel.
Just enter your new pixel width or height at the top. Make sure that “keep proportions” is checked and Graphic Converter will work out the other value for you.
At the bottom you can select various resample algorithms. Resizing to web quality you are unlikely to notice much difference between any of these. I usually leave it set to Lanczos 3 because that generally gives best quality and takes very little time. Hit OK and your picture is resized.
Now it's time to save it. File…save a copy as gets you this screen.
Look closely at the save panel and you'll see these options.
Choose where to save it and hit save - you will get a further dialogue
The dialogue shows your image twice. On the left is the original, on the right is the version compressed according to the options you set in the panel. If the quality looks bad then move the slider to the right. If the file is too big then move it to the left.
When you're happy, hit “OK” and Graphic Converter will save it.
| 
