The strongest Regenerate Thumbnails alternative for most sites is Force Regenerate Thumbnails, which not only rebuilds thumbnails but also clears out the old, orphaned sizes that Regenerate Thumbnails leaves behind. For rebuilding only chosen image sizes, AJAX Thumbnail Rebuild is more selective. If you also want to define new image sizes, Simple Image Sizes does both. We ranked these from our index of 55,000+ WordPress plugins.

Why people switch from Regenerate Thumbnails

• Regenerate Thumbnails does not delete old sizes, so people wanting a clean media folder move to Force Regenerate Thumbnails.
• People who want to regenerate only specific sizes rather than all of them move to AJAX Thumbnail Rebuild.
• People who also need to register custom image sizes move to Simple Image Sizes.
• Concerns about how actively Regenerate Thumbnails is maintained lead some to try Regenerate Thumbnails Advanced.

Force Regenerate Thumbnails – Clean rebuilds

Force Regenerate Thumbnails rebuilds all your thumbnail sizes and, crucially, deletes the previous ones first so you do not accumulate unused files. Against Regenerate Thumbnails, it keeps the uploads directory tidy rather than leaving old sizes behind. The drawback is that deleting old thumbnails before regenerating is a one-way step, so if a regeneration fails partway you can be left with missing images until it completes.

Choose Force Regenerate Thumbnails if you want to rebuild thumbnails and clear out the old sizes.

AJAX Thumbnail Rebuild – Selective regeneration

AJAX Thumbnail Rebuild lets you regenerate thumbnails for specific registered image sizes rather than forcing a rebuild of everything. Against Regenerate Thumbnails, it gives you finer control over which sizes to process, which saves time on large libraries. The drawback is that it is basic and updated infrequently, with a plain interface and no extra media tooling.

Choose AJAX Thumbnail Rebuild if you want to regenerate only certain image sizes.

Simple Image Sizes – Custom image sizes

Simple Image Sizes lets you create and manage custom image sizes and then regenerate thumbnails for them, all from the admin. Against Regenerate Thumbnails, it does more than rebuild: it also exposes and adds the sizes themselves. The drawback is that it is a broader utility than a simple regenerator, so its interface is more technical than you need if all you want is to rebuild existing sizes.

Choose Simple Image Sizes if you want to define new image sizes as well as regenerate them.

Regenerate Thumbnails Advanced – Bulk regeneration

Regenerate Thumbnails Advanced handles bulk thumbnail regeneration with options for cleaning up unused sizes and processing large libraries. Against Regenerate Thumbnails, it adds cleanup and batch handling in one place. The drawback is that it is less widely used and its interface is fairly basic, so it lacks the polish and track record of the more established tools.

Choose Regenerate Thumbnails Advanced if you want bulk regeneration with some cleanup built in.

When to stay on Regenerate Thumbnails

Stay on Regenerate Thumbnails if it already does the job when you change themes or add a new image size. It is a simple, trusted tool, and regenerating thumbnails is an occasional task, so unless you specifically want old sizes deleted or need to register new sizes, there is little reason to swap in a different plugin.

How we ranked these

Every plugin here is scored by the WPS Score, a single 0 to 10 rating built from 21 signals covering maintenance, support responsiveness, compatibility, performance, and ratings quality across our index of 55,000+ plugins. Rankings are derived from that data, not editorial preference, and no plugin author can pay to change a score. How the WPS Score works.

Frequently asked questions

Does Regenerate Thumbnails delete old image sizes?

No. Regenerate Thumbnails creates the new sizes but leaves the previous ones in your uploads folder, which can waste disk space over time. If you want the old sizes removed as part of the process, Force Regenerate Thumbnails deletes them before rebuilding.

When do I need to regenerate thumbnails?

You typically need to regenerate thumbnails after switching themes, changing the dimensions your theme uses, or adding a new registered image size. Doing so recreates the cropped versions for existing images so they display at the correct sizes across your site.

Can I regenerate only some image sizes instead of all of them?

Yes. AJAX Thumbnail Rebuild lets you pick specific registered image sizes to regenerate rather than processing every size. This is faster on large media libraries where you only changed one or two dimensions.

The verdict

The best all-round Regenerate Thumbnails alternative is Force Regenerate Thumbnails because it rebuilds and cleans up old sizes together, while AJAX Thumbnail Rebuild wins for selective regeneration and Simple Image Sizes for defining new sizes. If Regenerate Thumbnails already handles your occasional rebuilds, staying with it is perfectly fine.

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