Alt text generator for images
Alt text generator for images, uploads, and URLs
Most image workflows have the same small snag: the image is ready, but the alt text is not. I built AltCaption for that moment.
Drop in an image or paste a URL. Use the generated text as a draft, then add the things only you know: product names, page intent, or why the image is on that page.
Quick answer
To generate alt text from an image URL, paste the direct link to the image file into the URL tab of the AltCaption generator. The first 3 images work without an account. Edit the draft for the page the image is on before you publish it.
How to generate alt text from an image URL
Right-click the image in your browser and choose Copy Image Address (Copy Image Link in Firefox). That link opens only the image, not the page around it.
Paste the link into the URL tab of the generator on the AltCaption home page, pick a language, and generate. Copy the draft into your CMS alt text field, then add what the image can't show, like the product name or why the image is on that page.
Why a page URL doesn't work
AltCaption reads one image file per URL. A product page, a Pinterest pin or a Google Images results page returns HTML, so the generator asks for a direct image URL instead. The image has to be public and in PNG, JPEG, GIF or WebP format, up to 20 MB.
Use the image and the page together
The same image can need different alt text on different pages. A product photo on a category page may only need the product name and visible detail. The same photo in a repair guide may need the exact part being pointed out.
That is why I treat generated alt text as a starting point. The image gives the visual facts. The page tells me which facts matter.
Good output is boring in the right way
A good alt text generator should not write ad copy. It should not stuff the target query into every sentence. It should give me a clean description I can paste into a CMS field.
Concise output is easier to review. It is also harder to accidentally turn into keyword soup.
- Use a single sentence for most images.
- Mention text shown inside screenshots when it matters.
- Skip phrases like "image of" unless the medium matters.
- Do not repeat nearby captions word for word.
Examples
- Blue ceramic mug on a wooden desk beside an open notebook.
- Close-up of a Shopify product grid with missing alt text fields.
- Pair of white running shoes photographed from the side.
Common questions
What image formats work best?
Use clear product photos, screenshots, blog images, and gallery images. AltCaption supports common web image formats and direct image URLs.
How long should image alt text be?
Most images only need one clear sentence. I make it longer only when the image carries more information.
Do I need an account?
No. The first 3 images work without an account, and a free account adds 2 more. Pro is for bulk lists of image URLs.
Related guides
Generate alt text from an image
Upload an image, paste a URL, or use bulk generation when you have a list of image URLs.