The following guide is about how aspect ratios in Pokemon Go (and other Niantic/former Niantic products) affects image quality, and recommendations for people submitting (and voting on!) photos.
Short story: Square aspect ratio is the best ratio in all cases
Aspect ratio refers to the width to height of an image. Most cameras use a default aspect ratio of 4:3. But due to the mechanism of how images are processed, 1:1 square images appear best in-game.
Reason 1: 512 pixel image scaling
When images are loaded into Pokemon Go, the version that is loaded has a max height or width of 512 pixels. For a square photo, a 512 x 512 pixel image is returned. For any other aspect ratio, the longest side will be scaled to 512 pixels and the shorter side will be even smaller. The more extreme the aspect ratio, the smaller the smaller side will be.
It is then this scaled image which is used to make the photodisc in Pokemon Go. You can imagine this as effectively cropping to make a 1:1 circle.
I will illustrate this with two example images for the same Wayspot.
Example 1:
The original image is 4896 x 1250 pixels.
The image that gets loaded into Pokemon Go is 512 x 131 pixels.
The Photodisc then then displays a 1:1 circle, which is a 131 x 131 pixel crop.
Example 2:
The original image is 2282 x 2282 pixels.
The image that gets loaded into Pokemon Go is 512 x 512 pixels.
The Photodisc then then displays a 1:1 circle, which is a 512 x 512 pixel crop.
In game, example #1 looks blurry on the Photodisc photo whereas Example #2 looks sharp. This results from the scaling process; The image that ends up being used for Example #1 only has 6.5% of the pixels as the image used in Example 2. It is only 131 x 131 pixels, then blown up to fill the space of the Pokestop photodisc, resulting in a blurry image.
This diagram shows how the difference in effective image size used to make the Photodisc image on the Pokestop for the two examples. All images are correctly scaled relative to each other.
The below image shows the effect of this image scaling on the final Pokestop image. The left image shows what the outcome would have been if it was cropped to a square shape before scaling the longest side to 512 pixels. The image is crisp. The right image scales the longest side to 512 pixels first, then crops to 131 x 131 pixels image. The process for right image is what is used to generate Photodiscs, resulting in blurry images in game.
By comparison, because the square aspect ratio image (Example 2) scaled both sides to 512 pixels in the first step, the image used for the photodisc is the 512 x 512 pixel crop, which retains the maximum resolution.
Key takeaway: Using a landscape or portrait image – anything that is not a 1:1 square aspect ratio, will decrease the quality of the image that appears in the disc, even if the edges are ‘cut off’. Adding extra landscape in the cropped off edges for ‘scenic beauty’ will make your photodisc blurrier.
Reason #2: Postcard aspect ratio issues
The photos which are on Pokemon Go postcards squish non-square image to an incorrect aspect ratio.
For these reasons, there’s never a reason why not to use a 1:1 square aspect ratio. Even if it is something which you think would would benefit from a landscape or portrait ratio, you could take the same image as a 1:1 square by simply including more from the top/bottom or from the sides, e.g. below. This means that the centre image will remain high resolution, while also stopping the postcard from being squished.
Pokemon Go and other Niantic products could fix this in the following way:
- Instead of using the default googleusercontent url to load the images, which scales the longest side to 512 pixels, they could retrieve that url with
=s512-cappended to it. This would pre-crop the image to 512x512 pixels. This would result in a higher image quality with no change to what is rendered. - For the postcards, the team should mostly just fix it so it doesn’t squish the aspect ratio. But a similar strategy of using
-cwould probably also work. I suspect that postcards use a 128 pixel image version, so if they retrieved the url with=s128-cinstead of=s128then the image displayed by the game would always be square to begin with, and no squishing would occur.
(Also, given this thread might be linked to in the future for photo advice, I’m adding this image which has been shared previously on other platforms. It gives guidance for placement of the POI in the image frame. By having a bit of buffer room around the edges, it prevents key parts of the image getting cropped off, such as text cut off due to the circular Photodisc edges. Following this framing advice is good to ensure that images look good across all current and future Niantic products, regardless of how they end up displayed in game.)
