When you would like to use your own custom template for images then you also need to do some changes in the “core” database to show those images which use your custom image template in “Select Media” dialog.
You are able to see images but not yours then it looks like the following
To show your image, you should go “core” database and select the /sitecore /client /Applications /Dialogs /SelectMediaDialog /PageSettings /SearchConfigs /AllMediaFiles item. You should copy your image template to the “core” database and add this template in the “Base Templates” field. You should do the same for “ImagesUploadedByMe” and “RecentlyUploadedImages”.