Color problems after updating to 10.14.6 0n my IMac 27" . Images bleeding through and poor contrast. Particularly bad in Safari and Chrome browsers.

Hello Bagsy25,

Welcome to the Apple Support Communities. It sounds like there are several display issues in apps. I'll be happy to help.

Here are some suggestions:

• Restart your Mac if you haven't already from the Apple () menu then Restart...
• This might be related to video settings, so try resetting the PRAM/NVRAM: Reset NVRAM or PRAM on your Mac - Apple Support
• To narrow it down, also be sure to check your Mac in safe mode: Use safe mode to isolate issues with your Mac - Apple Support You can also try a new user as well: How to test an issue in another user account on your Mac - Apple Support

Thanks and have a great day.

Open System Preferences> Accessibility, click on Display and check Reduce Transparency.