Pixels, Resolution and PPI Explained Without the Jargon

Every digital photo is a grid of tiny coloured squares called pixels. Understanding pixels makes every resizing decision easier.

Pixels and dimensions

A photo's dimensions are written as width × height in pixels, for example 4000 × 3000. Multiply them and you get the total pixel count: 12,000,000, or 12 megapixels.

Megapixels	Typical dimensions
2 MP	1600 × 1200
8 MP	3264 × 2448
12 MP	4000 × 3000
48 MP	8000 × 6000

Resolution

In everyday use, "resolution" usually means the pixel dimensions. A higher-resolution photo has more pixels, so it holds more detail and makes a bigger file.

PPI and DPI

PPI (pixels per inch) describes how many pixels fit in each inch when an image is displayed or printed. DPI (dots per inch) is the printing equivalent.

• On screens, PPI hardly matters: only the pixel dimensions count. A 1000 × 1000 image is the same on screen whatever PPI is stored in the file.
• For printing, PPI decides how sharp the print looks at a given size. About 300 PPI is a common target for close-up prints.

Why it matters when resizing

• Making a photo smaller throws away pixels, so the file shrinks and detail drops slightly.
• Making it larger can't create real detail. The software has to guess new pixels, so enlarged photos look soft.

How many pixels do you need?

Use	Rough pixel width
Phone or chat sharing	1080 to 1600
Website or blog image	1200 to 2000
Email or forms	800 to 1600
Full-screen on a laptop	1920
Large print	as many as the original allows

A practical rule

Resize to a bit above the size you'll actually display. Anything more just wastes storage and upload time.

With a resizing tool

Choose exact dimensions when a site or form asks for them, or pick a smaller size to shrink the file. Keep the original untouched so you can resize again later.

Try Image Compress & Resize Tool →