Advanced Power of PHP

Change db engine in config file.

The same solution for both add and edit modes.

If you have knowledge in PHP you may do it with easy.
Simply look how it's done in the script and add in the same way additional image fields.

The script has MVC structure.

It's much better, faster and secure.
Please read this:
https://github.com/vladykin/miaow/issues/9

Use PDO extension for connection. PEAR will not work for you on PHP7
viewtopic.php?f=10&t=5418

Minification (also minimisation or minimization or minifying), in computer programming languages is the process of removing all unnecessary characters from source code without changing its functionality. Directy CMF allows you to enable this feature both for CSS and JavaScript. To use it you have to...

Read this:
viewtopic.php?f=33&t=2333

DataGrid doesn't support PEAR anymore, you have to use PDO.

Can you explain in more detail, what exactly is wrong?

Can you please turn on gebug mode and share us a link to your page?