[Mac only] When you move something with the move tool, it always snaps back to where it was before.
Change your color picker from Apple to Adobe. Go to Preferences > General > Color Picker: Adobe. You will have to quit and relaunch Photoshop for the change to take effect.

[Mac only] When you print to a PostScript printer from Photoshop 7 and specify a number of copies in the print dialog box, the printer makes many more copies than you asked for.
This is an OS 10.2 bug. Update to a higher release (10.2.2 or higher).

[Mac only] When browsing a folder of images, Photoshop quits.
Photoshop is crashing when generating a preview for an image. This is an OS 10.2 bug. A workaround until a permanent fix is made is to disable the AltiVecCore plug-in located in the Plug-ins > Adobe Photoshop Only > Extensions folder.

[Mac only] Your printer is hooked up via “LPR printer using IP,” and you are using the correct PPD file. Printing with other applications works fine. Printing with Photoshop results in mostly empty pages with strange icons at the bottom.
You need to send ASCII data to these LPR printers. Choose File > Print with Preview. At the bottom of the dialog, check the Show more options box. From the Output options, choose ASCII for the encoding.

[Mac only] Photoshop 7.x closes when Mac OS X v 10.2.x goes into sleep mode.
Disable sleep by going to System Preferences > Energy Saver > drag slider under “Put the computer to sleep” to Never.

[Mac only] Picture Package causes Photoshop 7.0.x to stop responding in Mac OS X. You have to force quit.
This happens after you have created a custom layout for Picture Package or have opened the Presets/Layouts folder for any other reason. Solution—install the Contact Sheet and Picture Package plug-in update found here.

Which should I use—adjustment layers, or the Enhance commands? They look like the same thing.

1. Always use adjustment layers. They are a thousand times better, safer, and more editable than the Enhance commands.
2. Adjustment layers have masks, blend modes, variable opacity, and can be edited or deleted at any time without harming or altering your image in any way.
3. Use them!

Is there any way to adjust individual color channels in Elements?
You do have limited access to the RGB channels in Levels.

1. Choose Layer > New Adjustment Layer > Levels.
2. Name the layer in the first dialog box, and then, in the Levels dialog box, click on the down arrow to the right of the Channel text box to find the three color channels.
3. Make different contrast adjustments to each color, if you wish, by clicking on each color in turn.
4. Use the two end sliders to increase overall contrast.
5. Use the center slider to increase contrast in one direction while simultaneously decreasing it in another. Be sure Preview is checked so you can see what you’re doing.

How can I simulate Photoshop’s History brush when using Elements?

1. Make a new layer at the top of your layers stack (use the New Layer button at the bottom of the Layers palette, or choose Layer > New > Layer).
2. Press Ctrl-Alt-Shift E to make a merged copy of your docuement on that new layer.
3. Turn off visiblity for that merged layer as you continue to edit the layers below.
4. When you want to add back part of the older version, turn visibility back on and use either the eraser or any of the various masking tricks to reveal that “history” state wherever you need it.

Can I make a duotone, or sepia tone image in Elements?
Elements does not allow you to make true duotone images, but you can create a similar effect as follows.

1. If you image is in grayscale mode, convert it to RGB by choosing Image > Mode > RGB color.
2. Choose Layer > New Adjustment Layer > Hue/Saturation.
3. After naming the layer (that dialog box pops up first), in the Hue/Sat dialog box, select the Colorize box in the lower right corner, and also click the Preview box (it should be checked by default).
4. Move the Hue slider around until you find a tone you like. Click OK.
5. You may need to add a Levels adjustment layer on top of the Hue/Sat one to add some contrast.

Method two - more unpredictable but more fun.

1. If your image is in RGB, remove the color from it by choosing Enhance > Color > Remove Color. (If it’s already in grayscale, skip this step; duh.)
2. If your image is in grayscale mode, you need to convert it to RGB. Choose Image > Mode > RGB Color.
3. Choose Layer > New Fill Layer > Solid Color. Name the layer, and choose Overlay from the Blend Mode drop down menu. You can do this in the Layers palette after adding the adjustment layer, so do it either here, or there, later.
4. Pick a color. Don’t worry too much about the color - you can always edit it later by double-clicking the adjustment layer icon which is the square on the left on the adjustment layer - the one on the right is the mask icon.
5. Click on OK, and then go to the Layers palette and lower the adjustment layer’s opacity to 40 % (experiment with that setting - that’s just a starting point). Opacity is in the upper right corner of the Layers palette. Type a value, or click the down arrow to find a slider.
6. Try changing the adjustment layer’s Blend Mode to Color. This gives a softer effect. The Blend Mode menu is in the upper left corner of the Layers palette. Make sure you have the adjustment layer selected when you change the blend mode.