PrestaShop Image Settings: Presets, Quality, Regeneration

PrestaShop generates a separate copy of every product image for every size it needs — thumbnail, cart icon, category listing, product page, and more. Understanding the Image Settings screen means you can stop guessing why images look blurry, slow, or wrong-sized.

1. Where the settings live

Design → Image Settings

Two sections matter:

• Image presets (the size templates)
• Image quality (compression)

Each uploaded product image is stored once, and PrestaShop generates one re-sized copy per preset — for cart, small, home, medium, large, and so on. These generated copies are what your pages actually display.

2. What each preset is for

The default presets each map to a page element:

Preset	Used for
cart_default	cart and checkout summary thumbnails
small_default	search results, cart block
home_default	category listings and featured products
medium_default	product page, related products
large_default	zoomed product image
category_default	category header banner
products_default	cross-sell and up-sell blocks

If your theme was built with custom sizes, the theme's documentation lists them. What matters: the preset size should match what the page actually displays. A 250×250 display slot served from a 500×500 preset doubles the bytes for no visible gain; a 500×500 image squeezed into a 250×250 slot is what makes images look blurry.

3. Image quality (the slider)

Under Image settings you set a compression percentage for JPEG (0–100%) and PNG settings.

What it really means:

• Higher = larger files, better looking. 90–100% for stores selling detail-critical products (jewelry, fabric, art).
• Lower = smaller files, more compression artifacts. 70–80% is the usual sweet spot for general merchandise.

The percentage applies when PrestaShop generates the presets. Changing it does not re-write anything by itself — you must regenerate thumbnails (next section) to see the effect.

4. When to regenerate thumbnails

The Regenerate thumbnails button rebuilds every generated image copy from the original. Run it when:

1. You change a preset's width or height.
2. You change the quality percentage.
3. You switch themes and the new theme expects different sizes.

Two warnings:

• It deletes and rebuilds. Take a backup of /img/ first — a small store is seconds; a large one takes minutes.
• Do not run it mid-day on a busy store. Regeneration is CPU-heavy. Run it in the quiet hours or on staging.

5. Blurry product images — the 3 causes

1. Preset size smaller than display size. The browser stretches the image up. Fix: set the preset to the actual display size (or larger for retina).
2. Quality set too low. Check the slider — 70% with heavy JPEG compression shows artifacts on detailed products.
3. Theme downscales but the browser oversamples. If the theme requests a preset but the layout shows it bigger, regenerate at the right size or adjust the theme.

After any change, regenerate thumbnails once — not twice, not in a loop. If images still look wrong after a clean regeneration, the cause is in the theme, not the settings.

6. WebP and modern formats

WebP files are roughly 30% smaller than JPEG at the same visual quality. PrestaShop 8 and 9 generate WebP alongside JPEG/PNG when the theme and modules support it. If your theme or modules do not, a CDN can convert on the fly (Cloudflare does this with one toggle).

WebP is the cheapest page-speed win you can get without touching layout — see how to speed up your store.

7. What NOT to change

• Do not shrink presets to "make the site faster" without checking the theme — you will make images blurry and get the same speed problem back from repeated regeneration.
• Do not delete the original uploads in /img/p/… — PrestaShop regenerates all preset copies from them.
• Do not regenerate thumbnails repeatedly hoping for a better result. It does the same work each time.

FAQ

Where are my product images stored? Originals in /img/p/ (product), /img/c/ (category), /img/m/ (brand). Generated preset copies live alongside them. Back up the folder before regeneration.

Why do my images look fine on the product page but blurry in the cart? Different presets. The cart uses cart_default; if it was set smaller than the theme's display, it looks soft. Match the preset to the display.

Can I add a custom image preset? Yes — Design → Image Settings → Add new image format. Give it a name and size, then regenerate thumbnails so existing products get copies. The theme must reference the preset name to use it.

Does changing image quality affect already-generated images? No. It applies only when images are generated. Run Regenerate thumbnails afterward to apply the new quality everywhere.