CREATING YOUR OWN USERPIC
If you want your userpic to include text, animation, or other graphic effects, you will need an image editing program. If you do not have an image editing program, you may wish to use your favorite search engine to find one. The image you create will need to fit LiveJournal's limit of 100x100 pixels, and a maximum file size of 40 KB.
If you have a paid account, you can use LiveJournal's ScrapBook photo hosting service to create a userpic. First, you will need to upload the photo to your ScrapBook account. In order for this to work, the photo must have a security level of public. Note that if you use an animated image, only the first frame will be used in your userpic. View the "manage picture" options for this photo. Then, click on "Upload/Manage user picture". You will then have the opportunity to create userpic keywords and comments, and decide whether you wish for the userpic to be your default. Finally, click "Proceed" to complete the process and add the photo to your userpic collection.
FINDING AN ALREADY-CREATED USERPIC
You can also find a userpic from a website or from a LiveJournal community. To find a LiveJournal community that shares userpics, see http://www.livejournal.com/support/faqbrowse.bml?faqid=85. If you find an image from a website or community, be sure that you are authorized to use the image and do not infringe on any copyright associated with the image.
CREDITING A USERPIC
If you want to credit the creator of one of your userpics, you may do so either on your User Information page, or by using userpic keywords (http://www.livejournal.com/support/faqbrowse.bml?faqid=95) or comments (http://www.livejournal.com/support/faqbrowse.bml?faqid=206). Some creators may require credit as a condition for using their userpic. In these cases, you should contact the creator to check what forms of credit are acceptable.
For instructions on uploading your userpics, visit http://www.livejournal.com/support/faqbrowse.bml?faqid=1.