I experimented with inside styles, div and span, but none of them do work in b2evolution. A small difference with greymatter.

The only way to get the same result is to make a class style for it and include like : img src="" class="" alt=""

No, that's not the only way, but it is the way I'd recommend. The other way is to open up conf/_formatting.php in a text editor and search for img. Wherever you find alt and the such in an arrary, match the formatting and enter style in there as well. It will probably take a few tries to get it right, so make sure you make a backup of the file before you start editing. If you get an error, make sure you've put style in the right places (there will probably be more than one, I haven't got code here to check on), and you match the correct formatting.

Graham: Thanks for the answer and the info.

By adding styles to the image tag itself, you are more flexible. A class is for standard situations.

I go to have a look at the file after back up one :-)