Threads Image Size in 2026: Aspect Ratios, Carousel Limits and File Limits

The safest Threads image size is 1080x1350 pixels, a 4:5 portrait that fills most of a phone screen and matches what most people already make for Instagram. Threads itself is more flexible than Instagram: Meta's Threads documentation accepts JPEG and PNG files from 320 to 1440 pixels wide, aspect ratios up to 10:1, up to 8 MB per image, and carousels of up to 20 images. Square (1080x1080) and landscape (1200x628) images work too.

What size should a Threads image be?

Threads does not publish a recommended pixel size. The sizes below are the common recommendations in 2026 guides (Linearity, PostEverywhere), and every one of them sits comfortably inside Threads' technical limits.

Width is the number to watch. The API scales anything narrower than 320 pixels up and anything wider than 1440 pixels down, so 1440 wide (1440x1800 at 4:5) is the largest image that keeps all of its pixels, at least through the API. Most guides stick to 1080 wide because the same file then works on Instagram, which stops at 1080.

What are the Threads image and carousel limits?

The 20-image carousel is recent. Hootsuite logged the increase from 10 on 14 July 2025, and Threads' own account confirmed in December 2025 that you can "add up to 20 images to a carousel" and reorder them before posting. One API rule catches out scheduling tools: since 22 December 2025, a post with more than five links fails when its media is created, so keep scheduled posts to five links or fewer.

Does Threads crop images in a carousel?

The sources disagree, so plan for the stricter answer. PostEverywhere (March 2026) says Threads does not force a crop and lets one carousel mix ratios. Linearity says every slide follows the first slide's ratio, which is how Instagram behaves by default. A Threads engineer wrote in July 2023 that "4:3 is the optimal ratio for our carousel if you don't want cropping", but that comment is old and does not say whether he meant portrait or landscape.

The rule that is safe under all three readings: give every slide the same ratio, either 4:5 (1080x1350) or 3:4 (1080x1440), and keep text and faces away from the edges in case a slide is trimmed. Threads does not document its carousel cropping, so post a short test carousel from your own account before you publish a long one.

Can you reuse Instagram images on Threads?

Yes. Both Instagram portrait sizes (1080x1350 and 1080x1440) and the square 1080x1080 fit inside Threads' limits, and both apps cap carousels at 20, so the same set of slides works on both. Two differences matter. Threads' API accepts PNG as well as JPEG, while Instagram's API takes JPEG only, so a scheduler that posts to both may need the JPEG version anyway. And Threads keeps widths up to 1440 pixels where Instagram stops at 1080, which only matters if you design wider than 1080 in the first place.

One difference runs the other way: Instagram's profile grid crops every post to 3:4, so a 4:5 post loses a sliver at each side there. The Instagram post size guide explains the grid and why scheduled Instagram posts should be 4:5.

How do you make an image at exactly the right size for Threads?

Decide the size before you design. In Canva or Figma, set a custom canvas of 1080x1350. In Claude Design, put the size in the first line of the prompt ("Design a 1080x1350 image post for Threads..."); the social post prompts show how. Claude Design can download one artboard at a time as a PNG at 1x or 2x, which is fine for a single image.

For a multi-slide carousel, Renda renders every slide of a Claude Design (or other HTML) export as its own PNG, numbered in order. It has no Threads preset; its Instagram 4:5 preset and Auto-detect, which renders the design's own canvas, both work, and the output is at 2x (2160x2700 for a 1080x1350 design). Threads' API scales anything over 1440 wide down and accepts PNG, so the files can be posted as they are. If one comes out over 8 MB, convert it to JPEG in a free tool such as Squoosh.

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