Image viewing on Kindle

As you may have learned, Kindle has an 'experimental' picture viewer. You won't find a description of this feature in your Kindle User's Guide, and most of the descriptions I've encountered in Kindle-related blogs and forums are incomplete and even inaccurate. I'll try to do better here, or at least no worse.

Preparing image content for viewing on Kindle

1. The viewer has native support for JPG, PNG, and GIF image formats.
2. Create a new folder (e.g. on the Desktop) that will contain the pictures for your picture album. Give the folder the name that you want to see in the Kindle's item list.
3. Copy the image files you want to use to the folder (.jpg/.jpeg, .png, .gif)
4. Consider resizing large images so they fit Kindle's screen better using a 3rd party image editing tool ('Irfanview' is a free, popular program for Windows that can do this. There are also free tools specifically for preparing image files for viewing on Kindle, like Mangle.) Anything that's reasonably small (say less than 1500x1500) will work ok, however.
5. Kindle will display the images in the alphanumeric sorting order of the filename. If display order matters, this is the time to rename the files so that the sorting order is the way you want them (e.g. 'img001.jpg, img002.jpg, ...). (Again, Mangle and similar tools will handle this for you.)
6. At this point, you can take the additional step of packaging the image files in a .zip file before putting them on your Kindle. I prefer this, since it not only saves some space, but it allows you to remove image content from the Kindle using its normal 'delete item' functionality. Kindle has to do a little more work to unzip for viewing, but the performance doesn't seem that much slower than if you copy a folder containing image content files directly. The procedure for creating a .zip file is similar on Windows and Mac:
1. Select the folder containing the image files. 
2. On Windows, right click on the folder and choose 'Send to - Compressed (zipped) folder'. On Mac OS X, right click (or Control click) on the folder and choose 'Compress [folder name].'

The next step is to copy the content to your Kindle:

1. Connect the Kindle to your computer using the USB cable; it should show up as a new drive named 'Kindle'.
2. Create a folder on the Kindle 'drive' named 'pictures' at the same level as 'documents'. You can actually skip this step, however, and just place image files in a subfolder of 'documents', or copy the .zip file created above in 'documents' instead.
3. Drag the folder(s) or .zip file(s) containing your image content from your Desktop to the 'pictures' folder.
4. Actually you can skip step 2. and just copy the folders and .zip files to the 'documents' folder, and it will work, but having them in a separate folder makes it easier and maybe more idiot proof when you want clean up (and you will have some cleanup to do at some point - see below)
5. Kindle will also read '.cbz' archive files ('comic book archive'). They are just .zip files with a .cbz file extension.
6. unmount/'safely remove'/eject Kindle.

Try it out

A new item should appear on your Home screen, corresponding to the name of the folder or .zip file with your image content. (If it doesn't press Alt, Z to refresh the item list. If it still doesn't appear, you'll have to hook back to the computer and check that it is in the right location). Open it like any other item, and the experimental image viewer will go to work. 

To maximize your enjoyment, it will be good to familiarize yourself with the available options:

1. There are some different Menu choices:
1. Disable/Enable Dithering - does this do anything? I don't notice anything..
2. Anchor to Top Right/Left - manga usually follow Japanese right-to-left convention. This lets you start in the correct corner when viewing at full resolution.
3. Disable/Enable Full Screen Mode - toggles the status bar at top 
4. Use Partial/Full Refresh - does this do anything? no idea...
5. Enable Pan to Next Page - useful for navigating manga/comics in full (larger than Kindle screen) resolution, navigates to previous/next page using 5way to pan.
2. There are some different Text (Aa) menu choices:
1. Actual Size (no | true) - view image at 'full resolution'; requires panning to view what does not fit on the screen
2. Scale (Fit Screen | Fit Width | Fit Height) - how to handle images whose aspect ratio does not match Kindle's screen, when Actual Size setting is 'no'. 
3. Screen Rotation (..the usual..) - view in portrait or landscape
3. Finally there are keyboard shortcuts corresponding to some of the menu functions. You will want to memorize a few of these, as they are far more efficient than using the menus & 5way:
1. 'f' toggles full screen, more convenient than using the menu.
2. 'r' rotates image 1/4 turn CCW and then back
3. 'q' zooms in (when not in Actual Size mode)
4. 'w' zooms out (")
5. 'e' reset zoom (")
6. 'c' toggles 'Actual Size'
7. Alt+G refreshes the pixels and removes 'ghosting' in the image viewer in image viewer, just as it does everywhere else on the Kindle.
4. And in case it is not obvious or expected, the page buttons advance to next and previous image.

Caveats/bugs/comments

• All of this should work on K2/DX/K3; I think on K1 as well.
• There are frequent redraw problems (parts of previous image not cleared). Tapping Menu a couple of times fixes this.
• Some of the menu settings are not 'sticky' from one session to the next and their menu status gets out of sync. For example, if you Enable Full Screen, the next image viewing session will have the status bar at the top, but the Menu will say Disable Full Screen instead of Enable Full Screen. Just tap 'f' to go to Full Screen.
• Kindle will save your reading position, but will not tell you what that position is, or when you are at the beginning or end, so you have no idea where in a particular sequence you are, it just cycles through.
• If Kindle goes into sleep mode, the screen will not redraw when you wake it up. Tap 'f' key, then Menu a couple of times to provoke redraw and remove artifacts. Or go Home and re-open the item.
• Another way of doing viewing images is to package your images in a PDF file, and use the PDF viewer (K2 or later models). Then you get page numbers, bookmarks, and (on Kindle 3) the useful contrast adjustment, and annotation, at the expense of some screen real estate (25 pixels on each side plus 55 pixels on the bottom). You can then also use wireless delivery as well (free using K3's wifi).  It is better than having Amazon convert it the .zip to AZW format (which the conversion service supports), because you can zoom for more detail, and you can't do that with images in any of the supported ebook formats. But this requires a way to create PDF from a set of image files. Mac (and most Linux) have this capability built in, but Windows users need to add software, or use a web conversion service, or make friends with someone with Acrobat.
• You can seemingly remove an image item from the Home screen using the usual 'delete item' function. However, if the images are in a folder, the folder and the files in it will remain on your Kindle. The next time the item list refreshes, the image item will re-appear. The only way to delete image folders is to hook up to the computer and use its file browser. On the other hand, if you have the image files in a .zip archive, 'delete item' will remove the .zip file, recover the space it took up, and the item will never reappear in the item list, but there will be a small '.manga' file left behind (Kindle creates this to save reading position). You can only remove this by tethering to a computer and using its file browser. No harm will befall you as a result of failing to remove the orphaned .manga files - but they do take up a tiny bit of space.
• Work is afoot to create an image viewing application for Kindle, presumably one with more advanced features and fewer bugs than what Kindle provides (e.g. search mobileread.com for 'mangle' - some references will be to the tool above, some for a Kindle app some folks are developing). I don't know if this or something similar will eventually appear on the Kindle Store, or will be something you can sideload to your Kindle. 
• There's no way to email image files for wireless delivery to your Kindle, apart from converting them to .AZW or packaging in a .PDF.
• I don't expect Amazon will ever officially adopt the image viewer and fix the bugs. Again, I think this will probably come in the form of an application in the Kindle Store before too long.
• calibre knows how to catalog .cbz/.cbr/.zip image files, but apparently does not (yet) know how to convert to an eBook format such as .mobi,.epub, or .pdf (something I'll suggest...). You can use it to copy .cbz/.zip files to Kindle, and it will put them in the 'documents' folder.