Match the width it is going to use anyway
Instagram displays feed images at around one thousand and eighty pixels wide. Uploading a four thousand pixel original means the app performs a heavy downscale followed by its own compression, and doing both at once is where detail is lost. Downscaling to that width yourself, carefully, leaves it with almost nothing to do.
This is why the preset here caps the width at that figure rather than something larger. It is not about saving bandwidth; it is about controlling which resize the picture goes through.
Aspect ratio decides what gets cropped
A square crop and a four by five portrait crop are the two shapes that display without surprises in the feed. Anything much wider is letterboxed or cropped by the app, and the app crops from the centre, which is rarely where you wanted the subject. Crop deliberately before uploading so that decision stays yours.
Where quality still visibly survives
Keep the quality high — the high eighties rather than the seventies — because the platform is going to apply its own pass on top of yours. Two moderate compressions stack into one heavy one, and the artefacts from the first become the input to the second. Compressing gently, once, gives a better final result than compressing hard and hoping.
Questions
- Why do my Instagram photos look blurry after posting?
- Usually because the upload was far larger than Instagram displays, forcing a heavy downscale and re-encode in one step. Resizing to around one thousand and eighty pixels wide yourself, at high quality, avoids that. Poor lighting in the original also plays a part, since sensor noise in dim shots compresses badly.
- Should I upload PNG or JPEG to Instagram?
- JPEG for photographs. Instagram converts uploads to its own format regardless, so a PNG gains nothing and uploads far more slowly. PNG is only worth using for graphics with flat colour and sharp text, where the lossless edges survive the conversion slightly better.
- What is the best aspect ratio for a feed post?
- Square or four by five portrait. Portrait occupies more vertical space on a phone screen, which is why it tends to perform better. Whatever you choose, crop to it before uploading rather than letting the app crop from the centre, which frequently cuts through the subject.