@miealex – You can over-write the thumbnail sizes when you insert the album using the IGW (“green button”) in its customization pane. You can also set this for all compact albums inserted going forward if you change that setting under Gallery > Gallery Settings > NextGEN Basic Compact Album.
As to removing the “# Photos” from the display, it would be best to create a custom template (keep a back-up of it as well) and remove the code that displays that detail.
Starting with a copy of the album-compact.php template, have a look at lines 44 through 46 (simply removing them should work just fine).
Save the copy/new template in the same location as the original and you are good to go.
Templates can actually be saved in one of two default locations:
/wp-content/themes/[yourtheme]/nggallery/
… or …
/wp-content/plugins/nextgen-gallery/products/photocrati_nextgen/modules/ngglegacy/view/
The back-up is for when you update either your theme or the plugin, unfortunately the WordPress core update process will remove your custom template depending on what is being updated.
Thanks!
– Cais.
PS: Please note, using the NextGEN Legacy “template” system will cause your thumbnails over-rides to be ignored. You may need to add the specific size you want to your custom template.