Drop the originals
Straight off a camera or out of a design tool — those are usually 4000px+ and 5 MB each.
Resize images for WordPress
Big uploads slow your site and break your Core Web Vitals. Batch-resize to 1600px and convert to WebP before you upload to the media library.
Drop images here
or · JPG, PNG, WebP, GIF
How it works
Set 1600 × 1600 and WebP
Pre-filled. WebP is 25–35% smaller than JPEG at the same visual quality and is supported by every current browser.
Upload to the media library
Smaller files mean faster uploads, faster pages and better LCP scores.
Questions
What image size should I use in WordPress?
For full-width content, 1600px covers most themes and retina screens without wasting bytes. Anything larger is served at a smaller size anyway.
Does WordPress support WebP?
Yes since WordPress 5.8 — the media library accepts WebP and serves it directly.
Will WebP break my theme?
No. WebP is served with a normal image tag; WordPress handles the mime type.
Is anything uploaded to a server?
No. The conversion happens in your browser. Only your own WordPress install ever receives the files.
WordPress image sizes that actually matter
WordPress generates a set of thumbnail sizes on upload. The one people miss is the "scaled" version, which silently kicks in above a threshold.
| Case | Value | Why it matters |
|---|---|---|
| Big image threshold | 2560 px long edge | Beyond this, WordPress saves a `-scaled` copy and uses that as the displayed image. Uploading larger just wastes disk. |
| Full size | As uploaded, up to the threshold | What the media library calls "Full". |
| Large | 1024 × 1024 | Default. Used in most theme content widths. |
| Medium | 300 × 300 | Default, rarely used in modern themes. |
| Thumbnail | 150 × 150 | Hard-cropped to square by default. |
| Hero / full-width | 1920–2560 px | Depends on theme. Check your theme container width before guessing. |
Five mistakes that waste the most time
Uploading 6000 px originals "for safety"
Above 2560 px WordPress creates a scaled copy and keeps the original as dead weight. Every backup and migration carries it forever.
Uploading 800 px images for a full-width hero
The browser upscales and the hero looks soft on any modern screen.
Ignoring WebP
WordPress 6.1+ generates WebP versions automatically, but an optimised WebP source is smaller than a JPEG source that gets converted.
Not compressing before upload
A 4 MB JPEG consumes hosting quota and slows the media library. Aim for under 300 KB per content image.
Relying on "Full" in posts
The full-size image is often far wider than the content column, so the browser downloads bytes it will never display. Pick a registered size instead.
Free web version vs the $19 desktop app
| Free, this page | Bulk Image Kit $19 | |
|---|---|---|
| Batch limit | 20 images | Unlimited |
| Preset 1600 px | Yes | Yes, plus custom |
| WebP output | Yes | Yes, plus PNG |
| Rename | Suffix | Pattern-based rename |
| Offline | After first load | Always |
More questions
What size should I upload to WordPress?
For blog content, 1200–1600 px. For full-width heroes, 1920–2560 px. Never exceed 2560 px unless you have deliberately raised the threshold.
Why did WordPress rename my file to -scaled?
The upload exceeded the big image threshold (default 2560 px). WordPress keeps the original for editing and serves the scaled copy.
Should I upload WebP or JPEG to WordPress?
WebP, if your theme and plugins do not break. WordPress 6.1 and later handle WebP natively. Keep a JPEG fallback for very old visitors only if your analytics says you need one.
Does resizing break my existing media links?
No. You are preparing files before upload. Never overwrite an existing media file — it breaks every post that references it.
Need more than 20 at a time?
Bulk Image Kit is the same engine as a single offline file — unlimited images, resize + compress + watermark + rename, one-time $19, no subscription.
See Bulk Image Kit — $19Other tools
- Bulk resize images in your browser
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- Compress PNG files without uploading them
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- Watermark a whole batch of images
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- Compress an image to under 100KB
- All-in-one bulk image tool