When it comes to Instagram and what image size to post I found myself confused. They are numerous recommendations online from a variety of sources. Some of those recommendations appear to be in direct contradiction while others are just clearly wrong. Even Business Insider, a seemingly reputable source, has at least one aspect of their suggestion wrong. Right in the middle of their article on the topic, they state:

A landscape (horizontal) photo should be in a 1.91:1 ratio.

They go so far as to post the following guidelines for different picture formats on Instagram, posting the incorrect aspect ratio for a landscape photo in the process.

Incorrect aspect ratio calculation for landscape photos on Instagram.

Do you see the obvious problem? A 1080 x 608 pixel image does not have an aspect ratio of 1.91:1. Does Business Insider not know how to do simple math? Clearly I won’t be taking any of their stock tips. The thing is, numerous sites seem to get this wrong as well. I assume they are all just copying information from each other rather than actually breaking out a calculator. Picmonkey gets it wrong. So does this site. At least Adobe knows how to do basic math. They suggest a landscape photo should have an aspect ratio of 1:91:1 with a size of 1080 x 566 pixels.

Aspect Ratio Calculations

To take a step back and clarify matters, calculating the aspect ratio of an image is simple. Simply divide the width of the image by the height. It’s not any more complicated than that. For example:

  • 1080 x 1080 pixels is an aspect ratio of 1:1
  • 1080 x 1350 pixels is an aspect ratio of 0.8:1, commonly expressed as 4:5
  • 1080 x 608 pixels is an aspect ratio of 1.78:1, commonly expressed as 16:9
  • 1080 x 566 pixels is an aspect ratio of 1.91:1

So why does this matter? Well if you’re one of the vast majority of people that post on Instagram, it probably doesn’t. Take a picture, post it, and you’re done. Your image may get cropped by Instagram, but if you’re just posting a quick selfie you probably don’t care. That’s fine, I wouldn’t either.

Size Does Matter

If your photography is important to you though, you’ll want to post your work to Instagram and have it displayed without any distortion or inadvertent cropping. Call me a purist, but I want the pictures I post for public consumption to be displayed as intended, not the way some algorithm thinks it should.

All this information left me confused, so I thought the best place to go was the actual source, Instagram itself.  Instagram states the following:

When you share a photo on Instagram, regardless of whether you’re using Instagram for iPhone or Android, we make sure to upload it at the best quality resolution possible (up to a width of 1080 pixels).When you share a photo that has a width between 320 and 1080 pixels, we keep that photo at its original resolution as long as the photo’s aspect ratio is between 1.91:1 and 4:5 (a height between 566 and 1350 pixels with a width of 1080 pixels). If the aspect ratio of your photo isn’t supported, it will be cropped to fit a supported ratio. If you share a photo at a lower resolution, we enlarge it to a width of 320 pixels. If you share a photo at a higher resolution, we size it down to a width of 1080 pixels.

The Magic of 1080 Pixels

You can see where the 1080 pixels in the examples above comes from. Instagram will display photos up to a width of 1080 pixels. If you upload anything wider that 1080 pixels, Instagram will shrink the image. If you upload a photo less than 320 pixels wide, Instagram will enlarge it.

Taking what Instagram claims they are doing at face value and believing they do what they say, then you should only post images between 320 pixels and 1080 pixels wide. Otherwise, Instagram will manipulate your image in some way in order to resize it for their needs. Most likely, posting an image wider than 1080 pixels and letting Instagram reduce it will have no visible effect on image quality. But I would also argue why take a chance and let Instagram manipulate your image when you don’t have to.

I’ve tried uploading the same image at resolutions of 1080 pixels wide and more, and on my phone at least, I didn’t see any discernable difference, for better or worse, with higher resolution images. For my money, there’s no reason to upload an image to Instagram that does not have a width of exactly 1080 pixels. Only the height of the image should be something other than 1080 pixels. That is where the aspect ratio comes into play, and this is where it all gets confusing.

Image Size Guidelines

According to Instagram, they will keep the picture’s original resolution as long as the aspect ratio is between 1.91:1 and 4:5. For images that are 1080 pixels wide, this translates to a height of anywhere between 566 and 1350 pixels.

In other words, as long as your image is 1080 pixels wide and between 566 and 1350 pixels tall, Instagram should post the image as is. At least in regards to the resolution and aspect ratio. Note that images 1080 pixels wide by 608 pixels tall meet that definition. They should be fine to post and not subject to manipulation. The only issue is that this image size is in a 16:9 format and not 1.91:1 as a number of websites state. A minor technicality sure, but annoying nonetheless.

Below are the correct image sizes to use when posting various formats on Instagram.

Instagram Aspect Ratios & Image Sizes
Instagram aspect ratios & image sizes to use when posting images.

Instagram: App vs. Desktop

There is one other caveat to be aware of that applies to the Instagram desktop interface, but not to the app interface. By default Instagram crops a photo to have a 1:1 aspect ratio. When in the process of posting an image using the desktop interface, Instagram allows the user to select a different aspect ratio if desired. The user can select from one of three standard aspect ratios, 1:1, 4:5, or 16:9.

This might sound obvious, but if anything other than the original aspect ratio is chosen Instagram will crop the original image as it sees fit in order to meet the aspect ratio that was selected. So even though an image might be at a resolution that meets all of criteria to avoid manipulation, if an aspect ratio besides the original ratio is chosen, Instagram will crop your image. On the app interface, when the user opts to select an aspect ratio besides the 1:1 default, no aspect ratio choices are displayed and Instagram automatically selects the original aspect ratio of the image. So in the app interface at least, there should be no inadvertent cropping. Just be aware that with the desktop interface cropping may occur if anything other than the original aspect ratio is selected.

Streamlining the Process

I always hated that for a long time Instagram would not allow users to post images from a desktop computer. As a photographer, all of my serious work was done on my desktop machine. I despised that I then had to transfer that work to my phone just so I could post it on Instagram. I was overjoyed when Instagram finally changed this arbitrary limitation and allowed images to be uploaded from my computer and eliminated a tedious and time consuming step.

For me, outside of a quick snap, I see no reason to ever upload an image to Instagram from my phone ever again. When I do post an image, I’ll make sure the image is 1080 pixels wide and between 566 pixels and 1305 pixels tall. I’ll also make sure that I choose to display the image in its original aspect ratio. That way I know the image posted will be exactly as I intended.