Why does my 48 MP phone save 12 MP photos?

Pixel binning. High-megapixel phone sensors combine groups of pixels — typically four or nine — into one larger effective pixel, which collects more light and produces a cleaner image. The saved file is therefore a quarter or a ninth of the sensor’s headline resolution unless the camera is deliberately switched into a full-resolution mode. This is why a customer with a 48, 50 or 108 MP phone almost always sends you a 12 MP file.

Is a higher megapixel count always better for printing?

For printing large, yes, all else being equal. But all else rarely is: a heavily compressed 24 MP file can print worse than a clean 12 MP one, and a full-resolution phone capture can be noisier than the binned version the phone would have saved on its own. Pixel count sets the ceiling; the quality of those pixels decides how close you get to it.

How do I work out the megapixels of a photo?

Multiply the pixel width by the pixel height and divide by a million. A 4032 by 3024 photo is 12,192,768 pixels, or 12.2 MP. The shape matters as much as the total, because a photo whose aspect ratio is far from the print’s loses more to the crop.

How many megapixels do you need to print a pet portrait?

It depends on the size, and by more than most charts admit. A standard 12 MP phone photo prints sharp up to A4 at 300 DPI and stays acceptable on a wall up to A3 at 200 DPI. The table below runs that calculation for every megapixel count a customer is likely to send you.

Every figure here accounts for the crop to each print's aspect ratio, which is the step most megapixel charts skip — and the reason their numbers come out flattering. Pick a size instead and you get the pixel dimensions every standard print size needs.

Effective DPI for each megapixel count at each standard print size, with cropping accounted for
Photo	5x7"	8x8"	8x10"	A4	11x14"	12x12"	12x16"	A3	16x20"	18x24"	24x36"
2 MP1,600 × 1,200	228	150	150	136	109	100	100	96	75	66	44
3 MP2,048 × 1,536	292	192	192	175	139	128	128	123	96	85	56
5 MP2,592 × 1,944	370	243	243	221	176	162	162	156	121	108	72
8 MP3,264 × 2,448	466	306	306	279	222	204	204	197	153	136	90
12 MP4,032 × 3,024	576	378	378	344	274	252	252	243	189	168	112
16 MP4,608 × 3,456	658	432	432	394	314	288	288	278	216	192	128
24 MP6,000 × 4,000	800	500	500	483	363	333	333	342	250	222	166
48 MP8,064 × 6,048	1152	756	756	689	549	504	504	487	378	336	224
50 MP8,192 × 6,144	1170	768	768	700	558	512	512	495	384	341	227
108 MP12,032 × 9,024	1718	1128	1128	1029	820	752	752	727	564	501	334

Effective DPI after cropping to each size's aspect ratio.Green clears 300 DPI,amber clears 200 DPI and is fine framed on a wall,red should not be sold at that size.

One page per photo size

What you can print from a 2 MP photo

1,600 × 1,200 px · 1.9 MP

Sharp to no listed size · acceptable to 5x7"

What you can print from a 3 MP photo

2,048 × 1,536 px · 3.1 MP

Sharp to no listed size · acceptable to 5x7"

What you can print from a 5 MP photo

2,592 × 1,944 px · 5.0 MP

Sharp to 5x7" · acceptable to A4

What you can print from a 8 MP photo

3,264 × 2,448 px · 8.0 MP

Sharp to 8x10" · acceptable to 12x16"

What you can print from a 12 MP photo

4,032 × 3,024 px · 12.2 MP

Sharp to A4 · acceptable to A3

What you can print from a 16 MP photo

4,608 × 3,456 px · 15.9 MP

Sharp to 11x14" · acceptable to 16x20"

What you can print from a 24 MP photo

6,000 × 4,000 px · 24.0 MP

Sharp to A3 · acceptable to 18x24"

What you can print from a 48 MP photo

8,064 × 6,048 px · 48.8 MP

Sharp to 18x24" · acceptable to 24x36" · usually saves 12 MP

What you can print from a 50 MP photo

8,192 × 6,144 px · 50.3 MP

Sharp to 18x24" · acceptable to 24x36" · usually saves 12 MP

What you can print from a 108 MP photo

12,032 × 9,024 px · 108.6 MP

Sharp to 24x36" · acceptable to 24x36" · usually saves 12 MP

Megapixels are the ceiling, not the answer

Two photos with the same megapixel count can print very differently. The count tells you how many pixels exist. It says nothing about whether those pixels carry any detail — and a photo that has been through a messaging app keeps its dimensions while losing the fine texture that makes fur read as fur, which is why a phone photo that looks fine on screen still will not print.

Shape matters too. A phone shoots 4:3 and a camera shoots 3:2, so the same 24 MP lands differently on a square print than on an 8x10 print — the crop comes off before the DPI is calculated.

When a customer's file falls short, the cheapest fix is asking for a better pet photo. The second cheapest is making sure they send the original without it being recompressed. Upscaling comes last. It invents nothing the camera did not capture.

Megapixel questions

How many megapixels do you need to print a pet portrait?: It depends entirely on the size. A 5x7 needs very little; a 16x20 needs a great deal. A standard 12 MP phone photo — 4032x3024 pixels — prints sharp at 300 DPI up to A4, and is acceptable framed up to A3. Megapixels alone never answer the question, because cropping to the print's aspect ratio throws away pixels before the print is made.
Why does my 48 MP phone save 12 MP photos?: Pixel binning. High-megapixel phone sensors combine groups of pixels — typically four or nine — into one larger effective pixel, which collects more light and produces a cleaner image. The saved file is therefore a quarter or a ninth of the sensor’s headline resolution unless the camera is deliberately switched into a full-resolution mode. This is why a customer with a 48, 50 or 108 MP phone almost always sends you a 12 MP file.
Is a higher megapixel count always better for printing?: For printing large, yes, all else being equal. But all else rarely is: a heavily compressed 24 MP file can print worse than a clean 12 MP one, and a full-resolution phone capture can be noisier than the binned version the phone would have saved on its own. Pixel count sets the ceiling; the quality of those pixels decides how close you get to it.
How do I work out the megapixels of a photo?: Multiply the pixel width by the pixel height and divide by a million. A 4032 by 3024 photo is 12,192,768 pixels, or 12.2 MP. The shape matters as much as the total, because a photo whose aspect ratio is far from the print’s loses more to the crop.

Check the photo you were actually sent.

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