In bed before going to sleep, bored at the airport, or while watching TV, I have thumbed through my Instagram profile and absentmindedly scrolled down the page perusing my portfolio of images. I have never thought much about them or the way they’re arranged—they’re just a collection of photos arranged in rows upon rows.

But that is not what other, more attentive Instagram users see. These users see The Grid. What is The Grid? It’s the overall presentation of your profile, what the individual tiles of images create when you zoom out to see them all. And there are some basic rules to creating a good Grid.

According to Louisa Wells, a photographer who also works as an Instagram consultant, first you should have a plan. “When you take images and prepare to post them, it’s always important to ask: Is this going to look good next to the last two images I posted?” This means that the Grid-dedicated don’t often post as things happen, waiting to compile aesthetically pleasing images in groups. “Spur of the moment almost never works,” Wells notes. She also suggests finding a color or filter theme—or even paying a little extra for photo apps like VSCO, Afterlight, Facetune, or even the planning app Planoly. “They help streamline the posting process,” shes says, and make the other steps easier.

But all of this careful planning is about to be interrupted. Last week, users began to see a change in The Grid. It appears as though Instagram is changing the number of tiles across from three to four, upending the carefully curated big picture that many dedicated users have spent significant time developing. “It’s been over a year that I’ve been formatting my Instagram in a multiple of three posts. I play with the overall look of my profile,” user Palash Prabhaker (@palxash), who creates tiled visual images on the app, told me via email. “I never had a design planned for my Instagram. All I knew was that if someone stumbled on [my account], they can scroll through my feed and get inspired.” Prabhaker, who noticed the change early last week, uses a combination of digital paintings and poems to create the mosaic.

Originally, he thought the new format was a glitch when he asked friends about the new format and they said it hadn’t changed. Instagram declined to comment on the record, but sources have indicated that this change to the format is merely a test.

“I regard my Instagram as a digital representation of me, I use my account as my digital portfolio,” says Prabhaker. “Messing with the grid view would mean that I will have to curate my Instagram again from the start with a constant fear of Instagram changing the layout again.”

The change could have something to do with phones getting bigger. That did not assuage Pabhaker’s concerns, though. “Now with a [four-photo] grid view, pictures look more like icons on your desktop.”

Prabhaker’s agony over the potential change may seem melodramatic, but then I stumbled into the world of #instagrids. Immediately, it was obvious how much careful time and thought was given into weaving these digital tapestries, and how the addition of a single image to the row would topple these sometimes massive murals.

Wells says the grid is important because it’s how we use Instagram to present ourselves and how we see others. What you do, she says, is “go into the app, you scroll and like, scroll and like—eventually you may click on someone who is tagged in the image of someone you follow. Then, what do you do next? You go to that person’s feed and start scrolling. Here’s the part that’s subtle—if you like what you see, what do you do next? You follow,” explains Wells.

“It’s almost a subconscious act that we find ourselves liking and following based on a few first images. The Grid is important because it’s your first impression. You have about 10 seconds to grab that person’s attention.”

Wells doesn’t think the change is as meaningful as some users may believe. Users complain, and then adapt. If four becomes the new grid format, then those who care about The Grid will adjust going forward. “I don’t think [the three-photo layout] is as important,” Wells says, “as the actual content that’s being posted.”