A GIF file format has a hard requirement most people don't think about: every single frame has to be exactly the same width and height. Real photos almost never come pre-matched that way — a phone photo, a screenshot, and a downloaded image can all have completely different dimensions and aspect ratios, and all of them need to end up the same size to become frames of one animation.
The "Contain-Fit" Approach
Rather than stretching photos to fill the target size (which distorts them) or cropping to fill it (which cuts off parts of the image), each photo is scaled down or up to fit entirely within the target canvas, keeping its original proportions intact. Whatever space is left over — above and below for a wide photo, or left and right for a tall one — gets filled with a plain white background, centered.
Two Worked Examples
Fitting a wide landscape photo (1600×900) into a 500×500 square canvas:
Result: 500×281 pixels, centered vertically (white space fills the top and bottom)
Fitting a tall portrait photo (900×1600) into the same 500×500 canvas:
Result: 281×500 pixels, centered horizontally (white space fills the left and right)
Both results stay fully within the 500×500 canvas, and neither photo's proportions get distorted — a square face stays a square face, a circular logo stays circular, regardless of the frame's original shape.
Why This Matters for Mixed Batches
Without this step, mixing a phone screenshot with a wide banner image and a square profile photo in the same GIF would either require manually cropping every image to match first, or produce an animation where each frame jumps between different canvas sizes — which most GIF viewers handle poorly or not at all. Fitting everything to one consistent size automatically means photos straight from a camera roll, downloads folder, or screenshot tool can go directly into the same animation without any pre-editing.
Mix any photo sizes into one clean animation
Try the GIF Maker