I have downloaded some icons but they all come in .psd format. I'm new to all this, how can I use the individual icons in this way? There are about 20 of them on one sheet.psd?
Do I need to use photoshop? What do I have to do to get individual icons from this to use?
Thanks so much!
GIMP is the best out of the listed alternatives for actually manipulating your file after it's opened, which it sounds like you're planning to do. In my experience, it is an excellent replacement for most of Photoshop and Illustrator. YMMV.
The link to Photoshop alternatives doesn't mention a few important caveats.
Your OS may not recognize GIMP as being able to open .psd files, but if you open GIMP then use its open command, the file will open.
If the .psd is in the CMYK colorspace, you may need to download a plugin. If so, be warned that colors may change slightly (or not so slightly) and this will matter if you're sending it to a printer or to another designer who will make further edits in Photoshop. If so, do a test print, warn the other designer, and/or find a computer with Photoshop.
Not all capabilites of Photoshop are correctly converted (I'm looking at you, Paths!), so be sure to save to GIMP's native .xcf format and inspect the details of the icons you're interested in, then make your modifications from there. In particular, moving a Path in GIMP will not move its Stroke, this must be done manually.
If you must crop, crop to each icon then save-as to its own .xcf, then export to JPG or other formats as needed.
You might not have to crop the image depending upon your use. Often, web designs load a large picture with all the icons on a page, then do the cropping themselves, and if you resize the file you may break that functionality. If so, the .psd you have represents an "Image Sprite"
Go to a computer with Photoshop, and crop the image into multiple png icons.
Alternatives to photoshop: