Resolutions for SD image generation

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When making images for StableDiffusion it’s best to take the aspect ratio in mind and make it fit into the total number of pixels that the model was trained on. This results in the best images for that given model. So, for SDXL it’s 1024×1024, others it may be 768×768 or even 512×512. Here is a list of effective X and Y values to total up to the most common aspect ratios for various training sizes. Obviously you would reverse the values if you go y/x.

1024x1024

Aspect Ratio 4:3 - Resolution: 1182x886
Aspect Ratio 16:9 - Resolution: 1365x768
Aspect Ratio 21:9 - Resolution: 1564x670
Aspect Ratio 1:1 - Resolution: 1024x1024
Aspect Ratio 3:2 - Resolution: 1254x836
Aspect Ratio 5:4 - Resolution: 1144x915
Aspect Ratio 16:10 - Resolution: 1295x809
Aspect Ratio 2:1 - Resolution: 1448x724
Aspect Ratio 18:9 - Resolution: 1448x724
Aspect Ratio 32:9 - Resolution: 1930x543
Aspect Ratio 3:1 - Resolution: 1773x591
Aspect Ratio 4:1 - Resolution: 2048x512
Aspect Ratio 5:3 - Resolution: 1321x793

768x768

Aspect Ratio 4:3 - Resolution: 886x665
Aspect Ratio 16:9 - Resolution: 1024x576
Aspect Ratio 21:9 - Resolution: 1173x502
Aspect Ratio 1:1 - Resolution: 768x768
Aspect Ratio 3:2 - Resolution: 940x627
Aspect Ratio 5:4 - Resolution: 858x686
Aspect Ratio 16:10 - Resolution: 971x607
Aspect Ratio 2:1 - Resolution: 1086x543
Aspect Ratio 18:9 - Resolution: 1086x543
Aspect Ratio 32:9 - Resolution: 1448x407
Aspect Ratio 3:1 - Resolution: 1330x443
Aspect Ratio 4:1 - Resolution: 1536x384
Aspect Ratio 5:3 - Resolution: 991x594

512x512

Aspect Ratio 4:3 - Resolution: 591x443
Aspect Ratio 16:9 - Resolution: 682x384
Aspect Ratio 21:9 - Resolution: 782x335
Aspect Ratio 1:1 - Resolution: 512x512
Aspect Ratio 3:2 - Resolution: 627x418
Aspect Ratio 5:4 - Resolution: 572x457
Aspect Ratio 16:10 - Resolution: 647x404
Aspect Ratio 2:1 - Resolution: 724x362
Aspect Ratio 18:9 - Resolution: 724x362
Aspect Ratio 32:9 - Resolution: 965x271
Aspect Ratio 3:1 - Resolution: 886x295
Aspect Ratio 4:1 - Resolution: 1024x256
Aspect Ratio 5:3 - Resolution: 660x396

So, if for some reason you need to calculate this on your own for some future or past resolution, here is the Python.

from sympy import symbols, Eq, solve

# Define symbols
x, y = symbols('x y')

# Equation 1: Total pixel count remains constant
total_pixels = 512*512

# List of common aspect ratios as tuples (width, height)
aspect_ratios = [
    (4, 3), (16, 9), (21, 9), (1, 1), (3, 2),
    (5, 4), (16, 10), (2, 1), (18, 9), (32, 9),
    (3, 1), (4, 1), (5, 3)
]

# Iterate over the aspect ratios and solve the equations
resolutions = []
for width_ratio, height_ratio in aspect_ratios:
    # Equation 2: Aspect ratio
    eq1 = Eq(x * y, total_pixels)
    eq2 = Eq(x / y, width_ratio / height_ratio)
    
    # Solve the equations
    solution = solve((eq1, eq2), (x, y))
    
    # Extract the resolution and convert to positive integers
    resolution = (abs(int(solution[0][0])), abs(int(solution[0][1])))
    resolutions.append((width_ratio, height_ratio, resolution))

# Print the results
for width_ratio, height_ratio, resolution in resolutions:
    print(f"Aspect Ratio {width_ratio}:{height_ratio} - Resolution: {resolution[0]}x{resolution[1]}")

As always, I guarantee nothing. enjoy.