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Tumblr Photo Post

1280×1920 JPEG · max

Each social platform crops uploaded media to its own aspect ratio before showing it in feeds. Uploading at the platform's native size — here, the platform feed posts — preserves the framing you intended and avoids the soft-focus that comes from the platform's own resampler. This preset outputs 1280×1920 JPEG at the portrait 2:3 ratio that the platform expects.

Specifications

Output dimensions1280×1920 pixels
Aspect ratio2:3 (portrait 2:3)
Output formatJPEG @ 92% quality
Processing100% in your browser — no upload
CostFree, unlimited
SourceOfficial guidelines

When you'd run Tumblr Photo Post

How Tumblr Photo 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 2:3 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 1280×1920 px as JPEG at quality 92%.

Where the work happens

Tumblr Photo Post crops your input to 2:3 and resizes it to 1280×1920 px as JPEG — a 2.5-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 Tumblr Photo Post output?

1280×1920 px, saved as JPEG at quality 92%.

Why crop to 2:3?

The target platform — see the cited spec — uses portrait 2:3 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 92%. 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.

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