I am thinking about which picture - size and dots per inch - i need to upload as a book cover for a kindle ebook.
Width at least 500 pixel
Height at least 300 pixel, and a maximum of 1280 pixel
Dots per inch should be 72 dpi
Now i want to buy a stock picture. I chose a picture and i can buy different sizes:
Small 658 × 729 px 23.2 × 25.7 cm @ 28.3 px/cm 420.71 KB 6 euro
Medium 1315 × 1460 px 11.1 × 12.4 cm @ 118.1 px/cm 1.48 MB 14 euro
Now i have no idea what size to choose.
The first one is bigger in dimensions - but this is irrelevant for screen i guess, i guess only the amount of pixels count - on the computer i guess you can make the picture any size you want.
Amazon says 72 dots per inch is good.
Now here i have pixel per inch.
I found in the internet:
To convert pixels/inch to pixels/cm, divide by 2.54.
To convert pixels/cm to pixels/inch, multiply by 2.54
-> got this info from paint.net and http://en.wikipedia.org/wiki/Dots_per_inch
With this calculation the first picture would be 72dpi
and the second one would be 300 dpi
I don't know where you got that information. The accepted standard for the Product Image is something on the order of 900x1200 pixels, 300 ppi.
This is much less important than it used to be, because in most cases there is no longer any Zoom feature to the Product Image. I think the only size that is available on the Amazon page is 300x300.
Most references I have ever seen use ppi and dpi interchangeably.
Within the book, images are to be no larger than 600x800 pixels (widthxheight) and again, 300 ppi, no larger than 127KB. I find 72 ppi perfectly acceptable. I use color when I have it, because the apps show color, and probably the KIndle will in the future.
That is directly from the Amazon Kindle Publishing Guidelines -
Help topics - Prepare your book - Formatting your book - Creating a Catalog/Cover image
Requirements for the size of your cover art:
Horizontally: minimum of 500 pixels
Vertically: minimum of 300 pixels maximum of 1280 pixels
Be sure to Save at 72 dots per inch (dpi) for optimal viewing on the web.
As far as I know we are talking about the image that Amazon will use to display on the Kindle book store page and its assumed people will be shopping for books at a desktop or laptop computer, not via a Kindle with a 600 by 800 screen. DPI for dots per inch is more correctly used to refer to printer resolution. PPI refers to pixels per inch and is used to refer to screen resolution. They are NOT the same thing although even nVIDIA refer to dpi in their graphics card utilities. I currently use a display with 95 by 93 ppi at 1920 by 1200 (20.5 wide by 12.75 inches high).
72 ppi is used as a de facto good enough resolution assuming it will be displayed on something like a 19inch diag monitor at 1024 res.
900 by 1200 would conform to the Amazon guidelines (500 minimum by 1280 maximum) but 300 ppi is way too high for display on screen. On a 20inch wide monitor you would need a horizontal resolution of 6,000 to be able to display all those pixels.
900 by 1200 would conform to the Amazon guidelines
(500 minimum by 1280 maximum) but 300 ppi is way too
high for display on screen. On a 20inch wide monitor
you would need a horizontal resolution of 6,000 to be
able to display all those pixels.
good name still guessing as YOU TOO have no idea re ppi/dpi and that it has NOTHING AT ALL to do with Images for Screen.
a screen displays PIXELS dude - why is that so hard to understand?
As far as book covers go, bigger seems to be better. A 600x800 image blown up to Amazon's maximum dimensions works out to 960x1280, and looks better, too, sans jaggies (pixelation often most noticeable around letters) and artifacts. Amazon accepts .jpg (also .jpeg) and .tiff (also .tif).* Saving an image as a .jpg automatically compresses it, and .jpg compression is always “lossy,” meaning that some data/image integrity is lost each time the image is saved. Images in .tiff format are, by default, saved without compression.
Since Amazon says this about catalog/cover images...
“KDP applies additional compression to images when displaying them on its website. For best results, images should be uploaded with minimal compression.”
...it's probably a good idea to upload cover images as .tiff images or, at the very least, minimally compressed .jpg images.
As long as your image is 960x1280 or smaller it will work, and at 72dpi, which is all you need for on-screen display. Any higher dpi than that, you simply end up with an image with more KB in it than are useful on-screen.
That said, it's almost always better to create your image(s) large, and in print-ready resolution (300dpi), so that you will have a useful source file ready for print (should you choose to offer print versions of your work), and so that you will have a high-quality source that can later be optimized for the web.
So, will the smaller image you've picked out suffice? Yep. (Maybe I should have said that first, saving the lengthy response.)
NOTE: Well, they used to. I just looked a moment ago at my covers and noticed that the very early ones no longer pop-up in larger size when clicked on (which would reveal some of the compression artifacts), but instead take readers into the book via the “Click to LOOK INSIDE!” feature. Those early covers were uploaded as 600x800, 72dpi, jpegs, and on the product page, they look okay. The most recent cover, uploaded a couple of days ago as an 800x1280, 72dpi, tiff image, shows up on the product page with the “ZOOM” feature (which none of the other, smaller ones, have).