I've been successful at locking my computer on "safesearch" when I use google images. This way I can still use google images but it blocks really bad stuff. The way I did it was I created a google account, which I made a VERY complicated password to with numbers, symbols, and upper and lowercase letters. I wrote down the password to create the account and used the account to lock safesearch on my computer. NOTE: You have to lock it on every single browser, (chrome, explorer, firefox, that you have), so be sure to save the password. Also it takes a bit of time for google to do this on each browser. After doing this rip up the password!
However, I still have access to yahoo and bing image searches and it is NOT GOOD. I can lock it, but I can also unlock it when I am weak. I need desperate help with this. PLEASE!