A post flops, and the first instinct is to blame the algorithm. Fair enough, it's an easy villain. But look at the post again before you do. Was the picture cropped in a weird spot? Did it come out looking mushy? Did it sit in the feed like a thin little strip when it could have filled most of the screen?
Those things are boring, and they're also fixable. People decide whether to keep scrolling in about a second, so a badly sized image rarely gets a second chance.
Here's what I'd check before posting anything: the right dimensions, a few quality habits, and how to write the text so the right people actually find it.
Size is really about screen space
Instagram lives on phones. Phones are tall. So a tall image simply takes up more of what the viewer sees, pushes the neighboring posts out of view, and stays a little longer in front of their eyes.
Put a landscape photo at 1.91:1 next to a 4:5 portrait of the same scene and the difference is obvious. One is a sliver. The other owns the screen for a moment.
Feed posts
- Portrait, 1080 x 1350 pixels (4:5). My default for almost everything. It claims the most feed space and doesn't get cropped.
- Square, 1080 x 1080 pixels (1:1). Still fine, especially for product shots, quotes and anything that sits neatly in the middle.
- Landscape, 1080 x 566 pixels (1.91:1). It works, but you're giving away screen space. Keep it for panoramas, or for scenes that fall apart when you squeeze them into a tall frame.
One more thing: Instagram has been nudging profile grids toward a taller 3:4 shape. If your profile page matters (for a business, it does), leave some margin above and below any important text so the grid doesn't slice into it. Post a few, then open your own profile and look. That tells you more than any chart will.
Carousels
You can add up to 20 slides, and people tend to spend longer on carousels simply because they swipe. The catch is that every slide should share the same ratio. Mix them up and Instagram trims the later ones to match the first, which is exactly how a headline ends up cut in half.
A pattern that works well: open with a slide that makes people curious, give the useful part in the middle, and finish by asking them to save or share it.
Reels: shoot vertical
The standard is 1080 x 1920 pixels (9:16). Film vertically from the start. Taking a horizontal clip and cropping it later costs you sharpness fast, and you'll see it.
Some things worth doing:
- Keep faces, captions and key objects away from the very top and bottom. That's where your username, caption and buttons sit.
- Choose your cover frame yourself. It shows on your grid, so pick one that's crisp and readable rather than letting the app grab a random frame mid-blink.
- Grab attention in the first two seconds with movement or a clear promise. Then actually deliver on it.
- Reels can now run up to three minutes, but a longer clip doesn't earn extra reach by itself. A short one that people watch to the end usually does better than a long one they bail on.
Why your images look soft, and what to do about it
Instagram compresses everything you upload. You can't turn that off. What you can do is hand it better material.
Start by exporting at the exact size you need. If you upload a 4000-pixel photo, Instagram does the shrinking for you, and it isn't gentle about it. Resize in your own editor first.
Save photos as JPG in sRGB color, because other color profiles can shift your tones after upload. Keep the file reasonably light too. A sharp 1080-pixel-wide JPG usually comes in at a couple of megabytes or less, and heavier files get squeezed harder.
Thin fonts and busy textures are the first casualties of compression, so lean toward bolder type and simpler backgrounds. For video, export an MP4 with H.264 video and AAC audio at about 30 frames per second. Steady, well-lit footage compresses far better than something dark and shaky.
If you often post on mobile data, check the app's data settings and switch on upload at highest quality.
What keeps people looking
The right size gets your post onto the screen. Holding attention is a separate job, and it comes down to a few simple choices.
Give the eye one place to land. If there are five competing details, it just keeps moving. Make sure text stands out from the background, and check that on a small phone screen instead of your big monitor. Faces and real expressions tend to pull people in more than abstract graphics do. A consistent color palette or layout helps too, since people start recognizing your posts before they read the name. And if someone needs a paragraph to understand a slide, that paragraph belongs in the caption.
Getting found: captions, keywords and alt text
Instagram search now looks at what a post is actually about, not just its hashtags. So the plain words in your caption matter more than they used to.
Think about how someone would type their question: "Instagram post size", "Instagram Reels dimensions", "best image quality for Instagram". If your post answers that, say so in normal language in the first line of the caption, where it counts most. Once is enough. If it reads like you're repeating yourself for a robot, rewrite it.
A few other habits help:
- Stick to three to five relevant hashtags. A wall of thirty rarely does anything these days.
- Fill in the alt text field with a short, honest description of the image. It helps people using screen readers and gives the platform another clear clue.
- In Reels, make the on-screen text and the spoken words match your topic, since both can be picked up.
- Post when your own audience is online. Your insights tab will tell you that better than generic advice will.
Before you hit post
Run through these quickly:
- Is the image 1080 x 1350 for the feed, or 1080 x 1920 for a Reel?
- Is it a JPG in sRGB, or an MP4 if it's video?
- Is the text bold enough to survive compression?
- Does the first line of the caption say what the post is about?
- Did you pick a cover frame and write alt text?
Five quick checks, and you've covered most of what makes posts look weak.
Instagram changes its specifications now and then. Before a big campaign, upload a test post and confirm the numbers in Instagram's own help pages.
More from the blog
- Facebook Image Sizes and Quality: How to Make Your Posts Stop the Scroll
- Image Resolution Explained: Pixels, Dimensions and Quality
- How to Rotate or Flip an Image Online
- How to Resize Animated GIFs Online
- How to Resize an Image Without Losing Quality
- How to Compress an Image to 100 KB (or Any Size)
- PNG vs JPG vs WebP: Which Format Should You Use?