Resizing changes the number of pixels. Compression changes the encoded file size. If a destination asks for a width of 600 pixels, use Resize. If it asks for less than 200 KB, use Compress. You may need both, but check the final result after each step.
Example: 1800 × 1200 to 600 × 400
Select the original and open Resize. Enter 600 for width: the linked height becomes 400. The original 3:2 ratio is preserved. Entering the height instead updates the width. The linked dimension is rounded to the nearest whole pixel.
A square requirement is different
A 3:2 photograph cannot become a square without cropping, padding or distortion. Toolkatsu currently preserves the ratio and does not offer cropping or padding. Use an already-square source if the destination requires a square.
Enlargement and limits
Resizing accepts 1–8,192 pixels per side and no more than 32 million pixels in total. Enlarging is interpolation, not AI detail reconstruction. A 300 × 200 image enlarged to 1200 × 800 may look softer despite having more pixels. Resizing keeps the input format, but the encoded file size may increase.
Before you save
Check both dimensions in the result, view the downloaded image at its intended display size, and keep your original. Re-encoding generally removes EXIF metadata; do not rely on the resized file to retain camera or location records.