Image resolution
Image resolution includes pixel dimensions and their relationship to presentation size; megapixels and pixel-density metadata describe different quantities.
A photograph measuring 6000 × 4000 pixels contains 24,000,000 pixel positions: 24 megapixels. That count says how large its sample grid is. It does not describe the scene's sharpness, lens quality or compression history.
Dimensions matter alongside the total
A 6000 × 4000 image has a 3:2 aspect ratio. Another image with 8000 × 3000 dimensions has the same 24-megapixel count but a much wider composition.
Cropping the first image to 6000 × 3375 creates a 16:9 picture with 20.25 megapixels. It removes 625 rows in total; it does not squeeze the original picture into that shape.
| Operation on the 6000 × 4000 source | Result |
|---|---|
| Retain the whole grid | 24 MP, aspect 3:2 |
| Crop to 6000 × 3375 | 20.25 MP, aspect 16:9 |
| Resize to 3000 × 2000 | 6 MP, same 3:2 aspect |
| Change density metadata only | Pixel grid remains 6000 × 4000 |
Halving each dimension quarters the number of pixels. This is why a useful browsing preview can require much less decoded memory than the original.
Density describes a physical-size relationship
At 300 pixels per inch, 6000 × 4000 pixels corresponds to approximately 20 × 13.33 inches. At 150 pixels per inch, the same samples correspond to 40 × 26.67 inches.
Changing that density label does not create another 24 million samples. Resampling to meet a physical-size/density target is a separate operation.
Screen presentation also has its own scaling and device-pixel ratio. A gallery tile's layout width does not necessarily equal the number of physical display pixels used to draw it. The resizing article develops that output-grid decision.
More stored pixels need not mean more recovered detail
Upscaling can create a larger grid and smoother-looking edges. It cannot restore scene detail that was never captured. Blur, missed focus or strong compression can remain apparent in a large file.
In an Emby photo or artwork view, distinguish the original dimensions, the server's generated image and the app's presentation size. A blurry small preview enlarged on screen does not establish that the full-resolution source is blurry too.