This tutorial includes brief instructions on how to crop your images in Photoshop and Picnik.

For the artist profile, your thumbnails must be a square, 65px x 65px at 72dpi.

Photoshop (or Photoshop Elements):

1. Open image
2. Click the crop tool or press C on your keyboard.
3. While the crop tool is selected, the toolbar will have 3 fields, width, Height and Resolution.  Enter 65px for the width and height and 72 for the resolution. It is important to include “px” on the width and height because older versions of Photoshop will assume inches.
4. Click and drag on the part of your image you want to crop to.  Notice the box will stay the same proportion as you drag. Then double-click in the box or right-click and choose crop to finish.
5. You should now have an image that is 65px x  65x at 72dpi. Go to file > Save For Web and export as a jpg.

Picnik (Free online image editing at http://picnik.com):

1. Upload your photo
2. Click the crop button
3. For the Constraints drop-down menu, choose Square and choose Scale Photo
4. Drag and choose the area you want to crop to. Click OK.
5. Click Save & Share tab.
6. You can probably leave settings alone, Dimensions will be what you cropped it as, format JPG (Best for most photos), JPG Compression Quality 8.
7. Click Save Photo.

For more options, Search in Google for “how to crop images.”