I use the Picasa image editor from Google these days for most of my basic photo editing and browsing on the desktop. I only turn to Photoshop for anything advanced that I can’t do in Picasa. Anyway, here’s a few little tips I’ve picked up.
For some reason, when I’m changing photos and saving copies, they don’t always show up immediately in Picasa. This seemed to be much worse in previous versions of Picasa, but 2.7 seems a lot better. If it does happen, try closing the application and restarting it, then usually the new versions will show up quite quickly. Alternatively, if you don’t want to do that or can’t wait, right-click your photo or the folder name and choose ‘Locate on disk’. This will open up the Explorer window at the correct location, showing your new photo.
When cropping a photo, hold down the Shift key to crop it to a square. Picasa doesn’t always manage to crop it exactly square, usually one or two pixels off. If you need real accuracy, use Photoshop or another editor. But for what I’m doing, almost-square is usually fine.
If you hold down the Ctrl key while dragging the crop box, it will crop it to a 640 x 480 (or 480 x 640) ratio.
If you hold down the Alt key while dragging the crop box, it will crop it to a 3 x 2 (or 2 x 3) ratio (the same as its 10 x 15 built-in crop ratio).
The Straighten tool seems to decrease the image quality, and I rarely use it; one of the tasks I jump into Photoshop for.
I tend not to use any of the Tuning or Effects tools, apart from the B&W one. What I do use a lot is the I’m Feeling Lucky and Auto Contrast, and to a lesser extent Auto Color. These seem to work with exactly the same effects as the Auto Levels, Auto Contrast and Auto Color under the Image > Adjustments menu in Photoshop. I’m Feeling Lucky seems to basically apply both Auto Contrast and Auto Color together. Most times it’s fine, but occasionally it makes the colours a bit odd. In which case, Undo it and try the Auto Contrast one instead.
Also make sure and apply any effects like this after you’ve finished cropping etc. If you apply the B&W or Sepia effect, I find adding Auto Contrast afterwards usually makes an improvement.
The only other thing I bother with is the Email tool to send photos, but it’s a bit quirky. This only seems to work if you have Outlook Express, a Gmail account or Picasa Mail, whatever that is. You can configure how it sends photos through the Tools > Options menu. There is a slider control that lets you say how large to resize the photos. It goes
You can either send the photo at its original size, or however wide you’ve chosen on the slider. If you’re sending more than one photo however, it will always resize them to the chosen width. To be honest, I’m not sure if the size is how wide it resizes, or just how long on the longest side.
When you’ve finished making changes and you want to save your photo, you can either use Save As, which just brings up a normal Save dialog box, or use Save A Copy, which will automatically save a new copy of the image in the same folder, with -1 appended to the filename (e.g. yourfile.jpg becomes yourfile-1.jpg). If there’s already a file with that name, it’ll save this one with -2, -3, … instead. I always just use the Save A Copy option for quickness. After saving my copy, I usually Undo all changes to the original image, so I can see the difference between the new one and my original.
That basically covers all my Picasa tips. There seems to be a lot more you could do with it if you wanted though. It still feels a bit like beta software, e.g. a set of tools called Experimental, and it has references to Hello, a photo sharing tool that has been offline since June 2008. Otherwise, I find it invaluable for working with all my photos. I daresay there are better tools out there for me, e.g. Adobe Lightroom.
See also the Picasa Wikipedia entry.