Resizing & fit modes

imgsqz can resize as part of the same pass that compresses and converts. Resize happens after EXIF auto-rotation, so width and height always refer to the visually upright image.

Resize by width or height

Set just one dimension and the other scales to preserve the aspect ratio:

# 800px wide, height auto
imgsqz photo.jpg --width 800

# 600px tall, width auto
imgsqz photo.jpg --height 600

Both flags require a positive integer (pixels).

Resize by both dimensions

Set --width and --height together and the --fit mode decides how the image fills that box.

imgsqz photo.jpg --width 400 --height 400 --fit cover

Fit modes

--fit accepts five modes (default inside). They only matter when both width and height are set.

Mode	Behavior	Aspect ratio	May crop?
inside (default)	Shrinks to fit within the box	Preserved	No
outside	Grows to cover the box, then you can crop later	Preserved	No
cover	Fills the box exactly, cropping overflow	Preserved	Yes
contain	Fits within the box, padding the rest	Preserved	No (adds padding)
fill	Stretches to the exact box	Not preserved	No

Picking a fit mode

• Thumbnails / avatars → cover (fills a square, crops edges).
• “Make it no bigger than N×N” → inside (the default).
• Exact canvas with letterboxing → contain.
• Don’t care about distortion → fill.

# Square avatar, cropping to fill
imgsqz avatar.jpg --width 256 --height 256 --fit cover -f webp

# Cap dimensions without cropping (fits inside 1200×1200)
imgsqz photo.jpg --width 1200 --height 1200 --fit inside

# Exact 16:9 canvas, padded if needed
imgsqz still.png --width 1280 --height 720 --fit contain

Upscaling

By default imgsqz never enlarges an image beyond its source dimensions — asking for --width 4000 on a 1000px-wide source leaves it at 1000px. This avoids blurry upscaled output.

Pass --enlarge to allow upscaling:

# Will NOT upscale a small source (stays at native size)
imgsqz small.jpg --width 4000

# Explicitly allow upscaling
imgsqz small.jpg --width 4000 --enlarge

Caution

Upscaling can’t add detail that isn’t there — --enlarge will make the file bigger and softer. Reach for it only when you specifically need larger pixel dimensions.

Resize + convert + compress in one shot

All of these compose. A common web-prep command:

imgsqz hero.png -f avif -q 50 --width 1600

That reads hero.png, auto-rotates, caps the width at 1600px (no enlargement), and writes a quality-50 AVIF.

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Next: Batch processing.