Photo

The term Photo is short for photograph which is a picture taken with a camera. It differs from other forms of graphics in its scope and implementation.

History

Photographs were popular as early as the 1850s. They used a box camera that captured the image on a single glass plate of film in black and white which was then developed in a lab and and transferred to photo paper. By the 1890s rolls of film were in use. In the 1930s color images were gaining in popularity. Cameras using film are now pretty rare with most cameras taking digital images. An actual camera is itself getting rare as it is being replaced with cell phones with video and photo capabilities.

While a photo refers to the image making process, a picture can be a photo, a painting, or a drawing of a distinct object. A picture may also refer to forming an image in your mind.

Use in eBooks

• illustrations or figures inside the books
• cover images.
• scanners, used to digitize images and OCR for text.
• a substitute for other book objects such as a table.
• An image can be of text to make an electronic copy of a page of notes.
• Multiple images can serve as an eBook, often in PDF's
• Electronic photo frames can serve as a reading device.

Formats

The most common format for digital photos is Jpeg but it is a lossy format so there are times when other formats are better to preserve the image.

• For ePub use only JPG, PNG and GIF are supported.
• For AZW and MOBI the PNG images will be converted to JPG or GIF images by the conversion software KindleGen.
• PDF has the widest support for images JPG, PNG, GIF, JXR, JPEG2000, TIF are all supported.

Descriptions of the formats:

• JPG - This generally produces the smallest file. This is the most popular image format in eBook readers and eBooks themselves. There are techniques that can be used to reduce the image file size by making the image less detailed.
• PNG - This is a lossless format but can be complicated. Some readers may not support this format at all or may only support 8 bit mode.
• GIF - A lossless format. This is great for graphic drawings but can also support photos with up to 256 colors. It is generally supported by eBook readers.
• JXR - A high compression photo with HDR support. Can be used in PDF files.
• HEIF - A recent format that supports both Wide color and Deep Color HDR. While this format is great for preserving the source image it is not supported by eBook readers.

Photo sizes

A digital camera may be able to take pictures using one or all of the ratios shown below. The larger number is listed first for landscape pictures. Generally if the camera can take pictures in multiple ratios the base ratio will be the 4:3 ratio. If you change to another one the longer dimension is maintained but the smaller size is reduced as needed to get the desired ratio. If you see the same first number under each ratio this is the dominate size for all but the square shape. For phones that include apps for the camera you might find the supplied app can only do one ratio but another camera app can be used to provide different ratios. Of course, it is also possible, after the picture is taken, to crop the image to achieve a different ratio. MP stands for Mega Pixel (million pixels) and is the standard measure for cameras which is approximately the value obtained by multiplying the two numbers.

16:9 ratio

This ratio used for 4" x 7" landscape pictures popularized by the APS, Advanced Photo System, cameras using 24mm film. These are also video standards.

Pixels	MP	Comment
1280 x 720	0.9	HD or WXGA720 video
1920 x 1080	2.0	Full HD video
2560 x 1440	3.7	QHD video
3840 x 2160	8.3	UHD video
4032 x 2268	9.1
4320 x 2432	10.5

3:2 ratio

This ratio used for 4" x 6" landscape images. Digital SLR's (Single Lens Reflex) use this ratio since it matches cameras using 35mm film.

pixels	MP	Comment
1536 x 1024	1.6
2400 x 1600	3.8
2464 x 1632	4.0
2592 x 1728	4.5
3008 x 2000	6.0
3872 x 2592	10.0
4032 x 2688	10.8
4290 x 2800	12.0
4320 x 2880	12.4
4920 x 3264	16.0
5380 x 3620	19.5	typical 35mm scanned image.
6000 x 4000	24.0	estimate
7360 x 4912	36.0

4:3 ratio

This ratio is used for portrait 5" x 7", 8" x 10", 11" x 14" by cropping the image. Matches VGA

pixels	MP	Comment
1024 x 768	0.8	XGA
1152 x 864	1.0	XGA+
1280 x 960	1.2	UVGA, iPad facetime
1400 x 1050	1.5	SXGA+
2048 x 1536	3.1	QuadXGA iPad screen size for 9.7"
2592 x 1944	5.0	rear camera iPad Air and older
3096 x 2322	7.0
3264 x 2448	8.0	iPad Air 2 and later models 9.7", 10.5"
4032 x 3024	12.2	iPhone 7 and later
4320 x 3240	14.0
4896 x 3672	18.0
5380 x 4035	21.7	Equal to 35mm quality

Square 1:1

This ratio, if supported, will commonly be one of the standard heights given above and then cropped to have an equal width.

Compare

• Compare with Nomenclature for standard sizes.
• Compare with Screen sizes to compare images with screens