PHP verification code does not show only one Red Cross solution

I did a verification code, but I don't know how to do it. there is always a red cross, but the verification code cannot be displayed. I found a good method after searching, if you have similar cases, you can refer to my recent attempt to learn PHP and have a verification code, but I don't know how to do it. there is always a red cross, but the verification code cannot be displayed, the reason is as follows:

The following error occurs before modification;

(1) the modification steps are as follows,

(2) click to open php.int .,
Search extension = php_gd2.dll
Open? Remove the semicolon and restart apache. it's okay. everything is fine.

I hope all of you can help me with this problem.