White fringe around my buttons

Hi, I'm using the trial version of Captivate 5 for Mac. I have 8GB RAM, OS 10.6.7, and pretty new Macbook. I'm trying to use the "next_black" series of three buttons (up, down, over). I'm using this so that I can pause the presentation after each slide and let the user click to continue.

Anyway, I have a green background behind the button, and it is showing a white fringe around the edges. I tried checking "Make Button Transparent" in the Properties > General tab, but that has no effect. I also edited the buttons in Photoshop and changed the background around the buttons from transparent to the green of my slides. Even after saving these in the gallery and selecting them under Properties > General > Browse, I STILL get the white fringing. I have tried quitting and restarting Captivate, but get the same thing.

So it appears that Captivate is still using the original image file with the transparent background. This is strange and seems like a bug to me. I am following the naming conventions for the buttons, by the way.

Here is a screenshot from the published presentation. There is no fringe apparent when working in Captivate, only the published version.

I like the program, but it seems kind of buggy in general. It didn't offer the project I'm working on as a "Recent Item" in the startup screen until I had opened it about 10 times in a row! And I usually have to click the name of the project two or three times before it will open. Still, I was able to produce a nice project, if I can just figure out the button deal.

Another thing--the forum search function isn't working. No results for "button" or "buttons" in "search this forum."

Thanks everybody!