For my Facebook photo profile I used a heart themed graphic. It started out in Photoshop as one of many shape graphics. I added color, used a bevel effect, and saved it as a red heart.
Next I created a layer and used a flower brush to create a collection of flowers.
Third, I saved a screened version as a pattern and saved the pattern as another layer.
For St. Patrick's Day I started a similar project, this time with Illustrator. I found a 4 leaf clover clip art on a free clip art site. I converted the SVG (scaled vector graphics) file to AI, added color and used a 3D effect. I also created a layer with screened clovers.
Brought this into Photoshop, created a yellow-gold background layer, sent to back. Saved a flattened version to Facebook.
If you use Illustrator you have symbol images that ship with the program. You can drag and drop the images into your project and scale them to the size you desire. You can also edit the file to give the image a unique look. Here's a sample.
For vector symbols covering biological and scientific subjects, you can't go wrong using the Integration and Application Network images (IAN). The details and links for free download are here. A sampling is shown below.
|Courtesy of the Integration and Application Network, University of Maryland Center for Environmental Science (ian.umces.edu/symbols/).|
You can also find vector art for purchase at Shutterstock, Dreamstime, and Veer to name a few vendors. Enjoy, and use wisely!