Problem with a circle GUI.

I set an circular image to
then I Draw a small button ,size = 38.

GUI.Button(new Rect(100, 100, size, size), " ");

unity draw a little circle with small lines in 4 direction but I dont need them.
I just want to draw a color selection button in circular shape like.
When I try size = 100, it fixed but I want to keep it small --a;


If there is anything I dont know and should know please tell me.
I’m quite new for both unity and GUI system so i’m sorry if this is a silly question.
Thanks everyone^^!

First, of course, it is necessary to check the size of a texture and if it is a circle, it has places where an alpha the channel is equal 0. Therefore it is better to do such texture in the psd format. Also it isn’t necessary to convert an animaniye on texture dpi when importing, all the same everything will be reduced to 72. Further I advise to create new GuiSkin and by operation with Gui to be guided by it (will add in public beginning the public GUISkin mySkin variable = null, and the in OnGUI function at the beginning such line = mySkin. Further, I advise in new Skin, to create one more style, for example, btn1 (GUI.Button should apply (new Rec(0, 0, 100, 100), “myButton”, “btn1”). It has same parameters, as well as at others. To us the border parameter is important, it gives an invariance of the size of a texture at the edges. And for invariable color of a texture it is necessary to add before GUI.Button the line GUI.color = Color.white. If to do a texture at which boundaries match with drawn, unity will expand it all the same on all rectangle. My decision following. The size 100 - all rectangle, the size 38 - a circle. It is possible to count a percentage ratio of a circle to all rectangle. Further to draw in psd, using this percentage ratio.