Thank you for your interest and for this question. By “image class” I assume you mean the CSS/HTML class attribute used in the gallery display. If that’s correct, the answer is yes.
You can define and use custom CSS inline style and HTML markup templates for the [mla_gallery]
shortcode. The “MLA Gallery” tab on the Settings/Media Library Assistent admin screen lets you view the default templates and set up your own custom templates. The “Documentation” tab explains this in the Style and Markup templates section.
I hope that gives you what you need to customize the gallery output to suit your needs. Let me know if you have any problems or further questions. Thanks for using the Media Library Assistant.