Why the platform ruins your image
Every social platform re-encodes uploads. They are serving billions of images and bandwidth is their largest cost, so they downscale to a target width and compress hard at settings you do not control.
Hand them a 12-megapixel file and their pipeline has to do a large downscale plus a heavy compression in one automated pass. Hand them something already at their target dimensions and lightly compressed, and there is much less left for them to degrade.
This is why the same photo can look crisp from one account and soft from another. The difference is usually what was uploaded, not the camera it came from.
The dimensions that matter
Widths are what platforms actually key on; heights follow from the ratio.
- Instagram square: 1080x1080 (1:1)
- Instagram portrait: 1080x1350 (4:5) — the most feed space of any feed format
- Instagram landscape: 1080x566 (1.91:1)
- Instagram Stories and Reels: 1080x1920 (9:16)
- Facebook feed post: 1200x630 (1.91:1)
- X / Twitter in-stream: 1600x900 (16:9)
- LinkedIn feed post: 1200x627 (1.91:1)
- YouTube thumbnail: 1280x720 (16:9), under 2 MB
- Pinterest pin: 1000x1500 (2:3)
Ratio decides the crop, not the pixel count
When a platform crops your image, it is because the aspect ratio did not match one it supports. Resizing alone does not fix that — a 3:2 photo resized to a square with the aspect lock off gets squashed, and with the lock on it simply is not square.
The correct sequence is crop to the target ratio first, so you decide what stays in frame, then resize the cropped result to the exact pixel dimensions.
The most common casualty is a face near the edge of a landscape photo posted as a square. The platform crops centrally, the face goes, and nobody notices until it is live.
Portrait wins on Instagram
The 4:5 portrait format occupies substantially more vertical space in the feed than a square, and dramatically more than a landscape. Since feed space correlates with how long a thumb pauses, this is a free advantage.
The trade-off is that portrait crops are harder to compose from landscape source photos, and if you also want the image on a website or a wide-format platform you will need a second crop.
Shooting slightly wider than you need gives you the room to crop for both without losing the subject in either.
Do not upload larger than the target
There is no quality benefit to uploading a 4000-pixel image where the platform serves 1080. It gets downscaled either way, and their automated resample is not better than one you do deliberately.
There is a real cost: larger uploads take longer, fail more often on poor connections, and on some platforms trigger more aggressive compression rather than less.
Resize to the target width, compress at quality 80, and upload that. The file will be a few hundred kilobytes and the result on the platform will be closer to your original than the full-size upload would have been.
Text and graphics need extra care
Photographic content survives platform compression reasonably. Text, logos, thin lines, and flat colour blocks do not — they pick up ringing and banding that is obvious even at feed size.
If your image is primarily a graphic, keep the text large and heavy, avoid thin fonts, and avoid subtle gradients behind text. Composing at the exact output dimensions rather than designing large and shrinking also helps, because it removes one resampling step.
Where a platform offers it, uploading as a PNG for graphic content sometimes survives better than JPEG, though most platforms convert to their own format regardless.
Profile images and covers
Profile pictures are displayed small and usually circular. Detail is wasted; contrast and a recognisable shape are what read at 40 pixels. Crop tight and check the result at thumbnail size before committing.
Cover and banner images are the most cropped assets on any platform, because they display at different aspect ratios on desktop and mobile. Keep anything important — text especially — well inside the centre, and assume the edges will be cut on at least one device.
Both are worth re-checking after any platform redesign, since these are the dimensions that change most often.
A workflow that holds up
Keep one high-resolution master per image. Crop from the master to each ratio you need rather than re-cropping an already-cropped export, which stacks quality loss and boxes you in.
Resize each crop to the platform's target width, compress once at quality 80, and upload. Three steps, in that order, every time.
If you post the same content across several platforms, the crops are the part worth doing carefully and the resize and compress are mechanical. Getting the crop right is what stops a face being cut in half on the one platform you did not check.
Frequently asked questions
What size should an Instagram post be?
1080x1080 square, 1080x1350 portrait, or 1080x566 landscape. Portrait takes the most feed space and is generally the best choice.
Why does my photo look blurry after uploading?
The platform downscaled and re-compressed it. Resize to its target width and compress at quality 80 yourself first so there is less left for it to degrade.
Should I upload the highest resolution I have?
No. It gets downscaled regardless, and larger uploads sometimes trigger more aggressive compression. Match the platform's target width.
Why did the platform crop my image?
The aspect ratio did not match a supported one. Crop to the target ratio before resizing so you decide what stays in frame.
What size is a YouTube thumbnail?
1280x720 at 16:9, under 2 MB. PNG exports frequently exceed the limit; JPEG at quality 85 has plenty of margin.
Does image size affect reach?
Not directly, but portrait formats occupy more feed space than square or landscape, which affects how long people spend looking at a post.