I just found out that someone owes a friend of mine a favor and so that person is willing to do my cover for me. I sent what I photos I want to use and the font.
But she wants to know what size is correct, and I suppose without asking ya'll that 300dpi is right for resolution or whatever dpi is called. And it seems I read on here that 800 X 600? for size or is that right?
As a side note, you need to consider the possibility of publishing a print version of the book, so get the designer to also create a version of the image which, at 300dpi, will print accurately to the dimensions of the print version of the book (so, for example, if you decided to do the print book at 6x9 inches, you'd need an image with pixel dimensions 1800x2700).
[i]The one to go in the book should be a JPG image, 600x800 pixels.[/i]
And under 127KB in size. This may require a bit of compression.
You probably will have a color cover. By all means use color when you upload it to the DTP for inclusion in your book. Though the Kindle shows only black/white, other apps will show color, and perhaps there will be a color Kindle in the future.
Although official guidelines are saying that your cover should be 600x800 pixels, my testing shows that images within a Kindle book can be 750x1000 pixels (width:height) and possibly even bigger if you use KindleGen to build your book. These should be JPEG files not bigger than 127KB in size. Based on my experimentation, the best compression options for JPEG images within a Kindle book are as follows: "progressive" with color resampling YUV411 or 2:1 horizontal and vertical resampling.
Regarding image resolution, my experimentation suggests that it doesn't matter. Your image within a Kindle book will look the same whether it is 72 dpi or 300 dpi as long as pixel dimensions are the same. In other words, an image with a bigger size in pixels will look bigger in a Kindle book, regardless of its resolution in dots per inch.
Sorry, I am not familiar with Paint Shop Pro. I use Ulead PhotoImpact and ACDSee PhotoManager. When you save a file as JPEG and click options, you see the compression options. Most graphics editors will show you percentage quality option and some will also let you choose the compression mode: Progressive (the best quality to size ratio), Standard, and Standard Optimized. There may also be an option of color resampling: 2:1 vertical and/or 2:1 horizontal, YUV411 subsampling (the best quality to size ratio), YUV422, and no subsampling.
I tried various JPEGs with KindleGen and it appears that Progressive mode plus YUV411 color subsampling produce the biggest book size, meaning that you have better quality of images in your book, all else being equal. For example if I try to build a book with two identical JPEG images (including identical size, say 126KB), but one of them uses no subsampling while the other was saved with YUV411 subsampling, then the book file with the latter image will be about 10KB bigger, suggesting that KindleGen did not try to recompress this image and you have better quality of your image.
I don't exactly understand it all myself, but "YUV" is the notation for analog colour subsampling, whereas "YCrCb" (as used in Paint Shop Pro) is the notation for digital colour subsampling. I [i]think[/i] "YUV411" corresponds to the setting "YCrCb 4x1 1x1 1x1" in PSP (though it's possible it actually corresponds to "YCrCb 1x4 1x1 1x1" - I can't find anything right now that would give a definitive answer to that one!).
When you use "File > Save As" in PSP, and select JPG format, then click on "Options" (bottom right of the "Save As" dialog"), you get options for: