Aseprite: How to increase image resolution and keep sharp edges

In this guide, you will learn how to make your images bigger without losing their sharp edges. This is called upscaling and the end result will have sharp edges without any blurring. Keep reading to find out how!

The why

There are plenty of apps that require a minimum resolution from images. This post’s branding image has a minimum image resolution of 195x195px, but the image I want to use is 8×8. Using Paint or online tools can cause the edges to become blurry and lose sharpness.

The what

This post will guide you throughout the whole process of upscaling the image resolution. Note that the result will have jagged/sharp edges with no blurring.

The how

Here is an example 8×8 sprite I made. This is the one that I will be upscaling to use as the image for the guide.

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It’s really small, the actual resolution is 8×8. It’s the same image as the one you see in the post title though!

Step 1 – opening the image

Open the image in Aseprite.

Step 2 – copying the image

Select all using CTRL/CMD + A and copy it with CTRL/CMD + C. You should see the dashed outline like in the image below.

Step 3 – creating a new file

Create a new file with CTRL/CMD + N and set the target resolution (how to calculate section is next).

Step 4 – calculating the new resolution

NOTE: The upscaled resolution should always be a multiple of the current resolution to preserve all detail
Pick an integer greater than 2 based on how much larger you want the resolution to be.

Here’s a handy formula to get the minimum number you should multiply the resolution by:

\(\left\lceil \max \left(\frac{target_res_X}{current_res_X},\ \frac{target_res_Y}{current_res_Y}\right)\right\rceil \)

Replace the X and Y for the target and current resolutions and paste it into an online calculator (Geogebra works) to get the result. Then, multiply X and Y respectively by the number you got from that equation (or the number you picked at random).

In my case, I have to multiply X and Y by 25, so I get 25×8=200 for each.

Type in the new resolution, and click OK.

Step 5 – pasting the image

Paste the image you copied in step 2 with CTRL/CMD + V.

Step 6 – resizing the image

From here, type in the new X and Y again in the third and fourth text box.

Step 7 – framing the image

Before pressing Enter, type 0 in the first two text boxes to move the image back to the canvas.

Step 8 – saving the image

Save your image as a separate file with CTRL/CMD + SHIFT + S, you’ll get a new window asking you to name the new file
Don’t forget to change the file type to a common format like PNG or GIF before clicking save!

Done!

Here’s the initial image:

And here’s the result:

And that wraps up our share on Aseprite: How to increase image resolution and keep sharp edges. If you have any additional insights or tips to contribute, don’t hesitate to drop a comment below. For a more in-depth read, you can refer to the original article here by 0x33, who deserves all the credit. Happy gaming!