In photoshop there is an area where you can go to draw your own pictures. YOu will actually use your mouse to control this feature this will allow you to draw your own circle. There is also a feature in this program that has basic shapes already imbeded into the program which you can manipulate to what size you need.
Open a document
1. select file and then new and make canvas 300*300 with 72 dpi in RGB mode and start a new layer. 2. click and hold rectangular marquee tool. choose the elliptical marquee tool. 3. drag that you will get an ellipse. hold shift key and drag the ellipse. 4. now fill and stroke your circle is ready.
There is already a circle in the tools section. In your toolbar there should be a button that resembles a rectangle, click or right click that and choose your shape. You can have custom shapes as well.
It is easy to create a circle in photoshop. Select the ellipse tool from the shapes and draw a circle. For better results press shift key while drawing.
Just choose on an own layer the painter tool and choose as size the aperture of your circle shape. Now the circle is selected. Switch the alpha channel value to transparency.