Image Dimensions vs File Size

Dimensions define pixel count

A 2000×1000 image contains two million pixels. Reducing both width and height by half leaves one quarter as many pixels, which often creates a large file-size saving before quality settings change.

Content and format change the bytes

Two images with identical dimensions can have very different file sizes. Noise, texture, transparency, file format, metadata, and compression quality all affect how efficiently the pixels are stored.

Use both controls together

Resize to match the destination, then select a suitable format and compression level. If a file is still too large, adjust quality carefully rather than reducing dimensions below what the display needs.