IrfanView
IrfanView (www.irfanview.com) is a very handy image viewer that can resize and compress your photos, and has many other tricks up its sleeve. It's free for personal use (but the author Irfan definitely deserves a donation). IrfanView now (version 4.2 on) has a very good Save for Web plugin.
To Crop:
- Quick crop: Drag the mouse to select the target area, then Edit » Crop Selection (Ctrl+Y)
- Precision/preset crop: Select Edit » Create custom crop selection (Shift+C)
- Set up the crop as required from presets or by entering the numbers, and press Apply to Image
- To adjust crop rectangle, drag edges (cursor becomes double arrow when over edge); hold down Ctrl while dragging to keep width to height ratio constant.
- To move the rectangle, hold down right mouse button and drag
- Select Edit » Crop Selection (Ctrl+Y) to do the crop
To Resize:
- Select Image » Resize/Resample (Ctrl+R)
- Enter the target width in the Set new size section (height adjusts itself as long as Preserve Aspect Ratio is selected), or choose one of the preset sizes.
- Make sure that Resample is selected as the Resize method. It's often a good idea to use the "sharpen after resample" option as well.
- Click OK
To Save for Web, you will need the relevant plugin:
- Select File » Save for web (type S).
- Adjust the Quality slider to reduce file size as far as possible while preserving quality (target: 20-40,000 bytes).
- To zoom in and out in the preview windows, hold down Ctrl and move the mouse scroll wheel
- Note the check box to update the preview automatically, also the option to compress to a given file size
- Click Save As to store the file, making sure you don't overwrite the original.