I'm using version 8.1 and this is how I would do it...
- File > New Image
- Set the size, and check the Transparent background
- Click on the Preset Shape Tool...in the toolbar, uncheck Vector and Retain Style, but check Anti-Alias
- Set your Stroke (the circle's outline) color and Fill (solid or gradient) color
- Press/hold Shift key, and drag a circle from somewhere in upper left corner of your canvas, then release
- This should draw your circle with the fill...then do whatever you want to your image
- When you're done and ready to save, go to File > Export > PNG Optimizer.....a window will open,
- Leave "Colors" tab defaulted
- Next tab "Transparency", make sure to check "Alpha Channel Transparency" and leave the other item defaulted
- Go to "Format" tab and (this is what I choose, but it's up to you) select "Non-Interlaced"
- Leave all other tabs defaulted
- Click OK....then give your image a file name and navigate to where you want to save it
- Click OK, and that should be it!
**Before doing the PNG optimize, you may want to first save the image (especially if it's multi-layered) as a resident .pspimage file...that way you can go back and work with the individual layers if needed...then go ahead and do the optimization. The Alpha Channel Transparency part is important if you want o maintain the transparent portions of your image.
Good luck!