SlashImage automatically compresses every image on your WordPress site, up to 90% smaller. Serves modern WebP and AVIF, so your pages load faster.
Same image: the original on one side, what SlashImage returns on the other. Drag across and see if you can spot the difference. (You won’t.)
Install the plugin, paste your key, walk away. New uploads optimize automatically; your existing library bulk-processes in the background. No babysitting.
Free on the WordPress.org repository, one-click install. Works on WP 6.0+ and PHP 7.4–8.3, alongside WooCommerce, Elementor, Yoast and the rest.
Sign up free (100 images/mo, no card). Copy your API key from the dashboard into the plugin settings. It runs a verification call and shows a green tick.
New uploads optimize automatically. Hit “Bulk Optimize” once for your existing media. AVIF and WebP are served to every browser that supports them, with an optimized original as fallback; your originals stay backed up.
A sunset, a dashboard screenshot, and a logo on a transparent PNG shouldn’t be compressed the same way. SlashImage looks at every image and picks the right strategy, so photos compress harder and screenshots stay crisp.
Every image is classified before a strategy is chosen. Photos get squeezed hard; screenshots, illustrations and logos are handled gently. Bigger savings where it’s safe, no banding where it isn’t.
Every output is checked against a perceptual quality model, the same family of metric used to tune AVIF. If a setting would introduce visible artifacts, we back off. You get the smallest file that still looks identical to the original.
Every image is delivered as AVIF or WebP wherever the browser supports it, with an optimized original as a fallback, generated and served automatically, no setup.
Two-stage processing keeps transparent UI assets pixel-perfect at the edges while still trimming the file size. No halos, no muddy alpha.
SlashImage serves a correctly-sized image per device with srcset, so phones don’t download desktop-sized files. Real bytes saved on top of the compression itself. Originals are always backed up, with one-click restore.
Create a separate sub-key per client site. Lock each to specific domains so a leaked key can’t be abused, and cap monthly credits so one runaway site can’t drain your account. Account-level allowlists and blocklists layer on top. (Sub-key creation is an Unlimited-tier feature.)
ShortPixel and Imagify are good products built on one-credit-per-output economics from before AVIF. SlashImage charges per source image. WebP and AVIF are free.
| ShortPixel | Imagify | SlashImage | |
|---|---|---|---|
| Unlimited monthly plan | credit-metered | $9.99 /mo | $8.99 /mo, unlimited |
| WebP + AVIF generation | extra credits | WebP only | both, 1 credit |
| Content-aware per image | |||
| Sub-keys + domain locking | API keys only | allowlist + cap | |
| Free tier | limited | 20 MB/mo | 100/mo, no card |
Competitor figures are illustrative. Verify against current published pricing before launch.
Start free, no card. Upgrade when you outgrow it, or never. No volume tiers, no surprise overage fees.
For small sites that don’t upload often.
For growing sites with a steadier upload cadence.
Truly unlimited. No cap, no throttle, no asterisk.
Free plan, 100 images a month, no credit card. Upgrade to unlimited for $8.99/month if your traffic justifies it later, or stay free forever if it doesn’t.