I would like to suggest a Mediapress WP All Import Add-on.It would users to import galleries and files from a csv or xls file using the WP All Import plugin. I was browsing through their site and on their add-ons page they have a section where plugin and theme developers can contact them to develop an add-on for their plugin or theme for free. Here is what it says:

“We Build It, You Bundle It

Don’t have the time to build an Add-On? We’ll make one for you.
For free. Really.

Too Good To Be True

We want as many people as possible to use WP All Import. While we are throwing some Pro features in to the Add-Ons for free, there are still a couple great reasons for users to upgrade to WP All Import Pro.

We also get support requests from users who run in to issues importing data into plugins and themes that use custom data structures, like storing serialized arrays in custom fields or using custom image galleries. With the Rapid Add-On API it’s cheaper for us to write an Add-On to solve these issues than it is to explain to people how to import this data. It’s also a much better experience for users.

These Add-Ons are great for us because we get to expand our user base and lower support costs. They’re great for you because your users get an easy way to import data in to their site and keep it up to date. And you won’t have to provide customer support for importing data ever again.

The Fine Print

This offer is for developers who have created publicly available themes or plugins. This is not for people who need help with a specific website or with a theme that you are using (or bought). If you contact us about making an Add-On for your plugin or theme there is, of course, no guarantee that we’ll agree to make it.

Every Add-On we make will be available for free on the WordPress Plugin Repository. Premium Support will be offered to Pro users through our support email address. Non-Pro users will be offered support via the Add-On’s support page on the WordPress Plugin Repository. We generally answer these support requests within a few days and we do our best to take care of everyone. However, we prioritize support to Pro users whose support requests we respond to as fast as possible.

Get Started Today

Send an email to support@wpallimport.com and tell us about your plugin or theme.”

I think this would be an excellent addition to Mediapress and should be fairly easy for them to accomplish given the Mediapress API. It would make migrations to Mediapress from other gallery plugins super simple. It may be something you want to look into.

Regards