Instagram Portrait Post ready
Files stay on your device. Enter send · Esc close drawers

Instagram Portrait Post

1080×1350 px · 4:5 portrait

Each social platform crops uploaded media to its own aspect ratio before showing it in feeds. Uploading at the platform's native size — here, Instagram feed posts — preserves the framing you intended and avoids the soft-focus that comes from the platform's own resampler. This preset outputs 1080×1350 JPEG at the portrait 4:5 ratio that Instagram expects.

Specifications

Output dimensions1080×1350 pixels
Aspect ratio4:5 (portrait 4:5)
Output formatJPEG @ 90% quality
Processing100% in your browser — no upload
CostFree, unlimited
SourceOfficial guidelines

When you'd run Instagram Portrait Post

About Instagram and this preset

Audience: 1.5+ billion users worldwide, skewing 18-34.

How Instagram ranks images: engagement-weighted feed favouring saves, shares, and watch-completion over simple likes. Posting at the platform's exact native dimensions (1080×1350 px) preserves your original framing and avoids the softening that happens when the platform's own resampler runs to fit its expected size.

Platform-specific note: Instagram crops feed posts to 4:5 in the timeline preview but stores the original aspect ratio; uploading at the platform's native size avoids the soft-focus that comes from the platform's own resampler.

How Instagram Portrait Post runs

This preset is a deterministic recipe — every step has fixed parameters so the result is byte-identical across runs of the same input.

  1. Crop the image to a 4:5 aspect ratio. Mochi keeps the centre of the frame in the middle of the crop by default — drag the crop box if you want to recompose.
  2. Resize to 1080×1350 px as JPEG at quality 90%.

Where the work happens

Instagram Portrait Post crops your input to 4:5 and resizes it to 1080×1350 px as JPEG — a 1.5-megapixel output. The work runs through canvas APIs and a WebAssembly image-encoder; the source image is decoded into an off-screen canvas, transformed in place, and re-encoded without any network upload.

Social-platform uploads frequently re-encode the file at the platform's CDN; running this preset locally before upload lets you see the exact pre-upload state. The browser-side path also means the file never leaves your device — relevant when the input contains personally identifiable information, screenshots of private documents, ID scans, or proprietary product photography.

Common mistakes

FAQ

What does Instagram Portrait Post output?

1080×1350 px, saved as JPEG at quality 90%.

Why crop to 4:5?

The target platform — see the cited spec — uses portrait 4:5 as its native frame. Submitting any other ratio means the platform's own crop runs, which often clips faces or text near the edge.

Why JPEG and not PNG?

The target accepts JPEG, and JPEG compresses photographic content 5-10× smaller than PNG with no visible difference at quality 90%. PNG is the right choice only when the image has hard edges or transparency — which photo-ID, social posts, and product photos don't.

Does my image get uploaded?

No. This preset runs entirely in your browser using WebAssembly + canvas APIs — no server round-trip. You can verify this in your browser's network panel: only static asset requests, no image upload. The file never leaves your device.

Related presets

All social media presets →