In short: in your WordPress dashboard, open ImageSEO → Bulk optimization. Choose which images to process, choose whether to rewrite all alt texts or only fill the missing ones, switch on titles, captions or file renaming if you want them, and click Start optimization. The optimizer works through your library in the background, in batches, and shows how many images were optimized or failed. Each image it processes counts toward your monthly images.
Before you start
Connect your account. The plugin needs a valid API key. You can create an account from the Welcome tab of the plugin or paste an existing key. See where to find your API key.
Check your credits. The Health tab shows “Credits remaining”. The free plan covers 10 images a month; paid plans start at 100. See pricing.
Pick the language. In the Settings tab, the Language field decides the language of the alt texts, titles, captions and file names. It starts on your site’s language.
In the WordPress admin menu, click ImageSEO, then open the Bulk optimization tab.
Under Images to optimize, choose which images to include (see the table below).
Under Optimize alt text, choose Optimize all ALT texts to rewrite every alt text, or Optimize only missing ALT texts to leave existing ones alone.
Switch on Optimize title, Optimize caption and Rename files if you want those too.
Click Start optimization.
Follow the progress in the report, which counts optimized and failed images. You don’t have to keep the page open.
The settings explained
Setting
Option
What it does
Images to optimize
Only Media Library images
Every image in your Media Library
Only featured images
Only images used as a featured image
Only WooCommerce product images
Product images (shown when WooCommerce is active)
Only NextGen Gallery
Images stored in NextGEN Gallery (shown when NextGEN is active)
Optimize alt text
Optimize all ALT texts
Writes new alt text for every selected image, replacing what’s there
Optimize only missing ALT texts
Only processes images that have no alt text yet
Optimize title
On / off
Also writes the image title
Optimize caption
On / off
Also writes the caption
Rename files
On / off
Gives the file a descriptive name and updates links to it in your posts and pages
How many credits will it use?
Each image the optimizer processes counts toward your monthly images. To use as few as possible:
Choose Optimize only missing ALT texts for your first run, so images that already have alt text are left alone.
Start with the images that matter, for example Only WooCommerce product images or Only featured images.
For a large backlog, take a bigger plan for the month you clear it, then move back down. New uploads are handled one by one as they arrive.
While it runs
The optimizer runs on your site in the background, in batches, using WordPress’s scheduled tasks (WP-Cron). You can close the tab and come back later. To stop a run early, click Stop optimizer; see how to stop a bulk optimization.
Troubleshooting
Open the Health tab and click Run health check. It checks the things that most often stop a bulk run:
Connection to ImageSEO shows “Unreachable”: your server can’t reach our API. Ask your host whether outgoing connections are blocked.
API key shows “Rejected” or “Missing”: paste your key again from your account.
Credits remaining is 0: the run stops when your monthly images are used up.
Plugin version says a new version is available: update first, because updates fix most problems.
Background tasks (WP-Cron) shows “Disabled”: the optimizer can’t run in the background. Ask your host to enable WP-Cron or set up a real cron job for WordPress.
If images show as Failed, check that they can be opened from the public internet. ImageSEO analyzes each image from its address, so images on a local or password-protected staging site, or behind hotlink protection, can’t be processed. If you’re still stuck, email support@imageseo.io with your site address.
