UBB.threads PHP Forum Software Community Forums UBB.threads 7 Bug Reports Did 7.5 Break CAPTCHA Images? -> No it didn't!

I had a new user report that they couldn't get a CAPTCHA image to show when trying to register on the forum. I tried creating a test account and verifed the problem exists. I was using Imagemagick and it was working in 7.4.2. The CAPTCHA image is now a rectangle with a red x. I've temporarily turned off CAPTCHA for new registrations.

I've never been able to get GD2 to display a correct CAPTCHA image - it's always a black marble looking image with nothing readable. Imagemagick paths in the control panel are /usr/local/bin/convert and /usr/local/bin/mogrify

Anyone else see this problem after the upgrade to 7.5? Any ideas on how I can fix GD2 (not related to the upgrade)?