Where are my image backups stored?
3 min read · Last updated September 2026
SlashImage saves a copy of each original image before it replaces it with the optimized version. By default it uses Smart backup, which stores only the full-size original and rebuilds thumbnails on restore, so backups take far less disk space. Backups live in your WordPress uploads folder, in a subfolder named slash-image-backups:
wp-content/uploads/slash-image-backups/Inside it, backups mirror your uploads by year and month, so an image uploaded in March 2026 has its backup under 2026/03. These backups are what make it possible to restore an original.
Images imported from another optimizer have no SlashImage backup, because SlashImage never held their originals. Those stay in the other plugin's own backups.
Backup mode: Smart backup or Full backup
The Backup mode control in the Backups section at Media > SlashImage has two options. It only appears while Keep backup of originals is on.
| Mode | What is backed up | What restore does | Disk use |
|---|---|---|---|
| Smart backup (default) | Only the full-size original | Puts the original back, then rebuilds every thumbnail from it using your current image sizes | Low |
| Full backup | The original and every thumbnail | Puts every file back exactly as it was | High |
The help text for Smart backup reads "Backs up only the original to save disk space. When you restore, thumbnails are rebuilt from it using your current image sizes." For Full backup it reads "Backs up the original and all its thumbnails, so a restore brings everything back exactly as it was. Uses more disk space."
Switching modes only affects images optimized from then on. Each backup remembers which mode made it, so restore always does the right thing for that image.
Settings that control backups
All three are in the Backups section at Media > SlashImage.
| Setting | What it does | Default |
|---|---|---|
| Keep backup of originals | Saves a copy of every original before it is replaced. Turn it off and new optimizations stop creating backups. | On |
| Backup mode | Smart backup or Full backup, as described above. | Smart backup |
| Auto-delete backups | Deletes backups older than the number of days you set. Set it to 0 to keep them forever. | 90 days |
The help text for Auto-delete backups reads "Delete backups older than this many days."
Delete all backups
To clear every backup at once, go to Media > SlashImage, open the Settings tab, scroll to the Danger Zone, and click Delete all under Delete all backups. Its help text reads "Permanent. Removes every file under uploads/slash-image-backups/ and clears the backup index. You will not be able to restore originals after this."