Instagram's square picture format harks back to the days of Polaroid cameras, where you'd take a snap, watch the image develop in front of your eyes, then write a comment in the space below. While this gives the social media platform an iconic look, it also means that unless you choose the square option on the iPhone camera app, you're going to lose some of your image when uploading to the service.

People have found a way around this by adding either horizontal or vertical borders to the images, but this can be time-consuming. Thankfully, several apps are now available that can do the heavy lifting for you. In this article we show how to upload a full-size image to Instagram, directly from your iPhone. No crop required.

(Want to use the app on your tablet? Here's how to get Instagram on iPad.)

Upload photos using Square Fit

There's a good selection of apps that can make your photos compatible with Instagram's format, and one of our favourites is Square Fit. This is available for free on the App Store, with a Pro tier that brings additional features for £9.99/$9.99.

Once you've downloaded and installed Square Fit, launch the app to get started. You'll notice pop-up ads and banners, all of which are removed in the Pro version, but for now these are the minor inconvenience that allows us to use it for free.

How to upload a full-size photo on iPhone to Instagram: Square Fit

On the main screen you'll see a row of icons at the bottom. In the left hand corner is NEW with a camera image above it. Tap this and then select the icon that looks like two Polaroid pictures. You'll be able to select which photograph you want to use.

Once selected, the image will be displayed in the main screen, with white borders around either side. Those are there to make the image into the square shape that Instagram requires.

You could leave it like that and save the image if you want, but Square Fit has a few tools that can make the image look more professional.

How to upload a full-size photo on iPhone to Instagram: Square Fit

Tapping on the SIZE button cycles you through three different layouts. These are the original one you were presented with, a zoomed-in variant that removes the borders, and a zoomed-out one that adds small borders around the other two sides.

For now leave it on the original selection, as there's another setting we'll be using to enhance its aesthetics.

Scrolls along the row of icons until you see PRESETS. This works in a similar fashion to SIZE, moving you through the various settings by tapping on the icon.

One adds blurred borders that contain the outer edges of the image. This mean that the colours are consistent, and look better than the white lines of the original. The next option adds the same area of the photo, but this time there's no blur.

For some uses this could be cool, if you have an photo that is simple, but for cluttered or busy shots it can look a little odd. Still, horses for courses and all that.

How to upload a full-size photo on iPhone to Instagram: Square Fit

When you're happy with the effect, tap the Save option in the upper-right corner. The new image will now be placed in your Photos library, making it available for Instagram. Just open the app, press the '+' icon in the middle of the bottom row, select your newly edited image, and it will be the right size for your social media feed.

How to upload a full-size photo on iPhone to Instagram: Save

To see how you can also access the photo sharing platform on a bigger screen, read our How to use Instagram on a Mac feature.