For the images  that are stored in tables in Ax, there is "Publish Images" functionality to push them to the web server. If you have custom tables which contains images and would like to include them as part of "Publish Images" for it to appear in Enterprise Portal pages, you should customize the SysEPDeployment class in AOT.

In SysEPDeployment class deployCompanyImages method, you should add deployImages(<TableName>), where <TableName> is the new table that you added.