WordPress Plugin Image Import Fix

My custom WordPress plugin relies on the standard wp.media frame to let users pick several images at once, store their attachment IDs, and immediately display those thumbnails inside the plugin interface. Everything looks normal inside the Media Library—images can be selected—but after I click “Select,” nothing appears in the plugin UI. The images are simply not imported, and the problem shows up inconsistently (random images fail while others occasionally work).

Scope of work
• Trace the point where the selection callback should receive the chosen attachment IDs and pinpoint why the data never reaches the display function.
• Check both the JavaScript that handles the media-frame “select” event and the PHP that stores attachment data, including any AJAX or REST handlers.
• Ensure imported images display instantly in the plugin interface and remain saved on page refresh.
• Test with multiple file types and sizes to confirm the fix works across all images, not just the ones that previously succeeded.

Acceptance criteria
• After selecting any number of images, their thumbnails appear immediately inside the plugin panel.
• IDs are correctly saved to the database (post meta / custom table as currently implemented).
• No JavaScript or PHP errors are thrown in Console or debug.log.
• Behaviour is consistent regardless of which images are picked.

A staging site with WP_DEBUG enabled and a copy of the plugin is ready; version control (Git) preferred for the patch.