Resize, convert and make thumbnails with the cPanel Images tool

Large photos straight from a camera or phone make web pages slow. The Images tool in cPanel can shrink them, create thumbnails or change their format directly on the server, which is useful for a gallery folder on a static site or a batch of product pictures. It has three parts: Thumbnailer, Scaler and Converter.

Before you start

• Upload the images to a folder in your account, e.g. public_html/gallery, with File Manager or FTP.
• Keep an original copy. Scaling and converting overwrite files unless you choose to keep a copy.
• For WordPress, use its built-in image sizes and an optimisation plugin instead; see WordPress image optimisation.

Create thumbnails (Thumbnailer)

1. Open cPanel → Files → Images and click Thumbnailer.
2. Click the folder icon to browse, then click the folder name that contains the images.
3. Set Scale Percentage for width and height, e.g. 25 %. Keep Keep Aspect Ratio ticked.
4. Click Thumbnail Images.

cPanel creates a subfolder named thumbnails with copies prefixed tn_, for example thumbnails/tn_photo1.jpg. Your originals stay untouched.

Resize images (Scaler)

1. Click Scaler, browse to a folder and click an image file (Scaler works on one image at a time).
2. Enter new dimensions in pixels or a percentage. With Keep Aspect Ratio ticked, changing the width updates the height.
3. Tick Retain a copy of the old image and choose a name, so you keep the original.
4. Click Scale Image.

Convert formats (Converter)

1. Click Converter, browse and click a single image or a folder.
2. Choose the target format, for example jpg for photos or png for graphics with transparency.
3. Click Convert. Converting a folder processes every image in it.

The Converter offers classic formats. For modern WebP or AVIF images, use a desktop tool or, on LiteSpeed servers, the image optimisation in LiteSpeed Cache.

After resizing

• Update image links in your HTML if the file names changed.
• Clear the browser and site cache to see the new versions.
• Check Disk Usage: thumbnails and retained copies use space and inodes.

Troubleshooting

• Nothing happens on a big folder: thousands of large images may time out. Process subfolders separately.
• Images look blurry: you scaled down too far, or scaled an already small image up. Restore the original and choose larger dimensions.
• Original overwritten: restore it from JetBackup.

Next steps

• Stop others hotlinking your images
• Serve modern image types correctly