To get screensaver images of my choice onto the Kindle Touch (the one without the special offers) required several steps:
- Jailbreaking the Kindle Touch
- Installing the screensavers hack
- Gathering the images
- Formatting the images
- Grouping and renaming the images
- Transferring the renamed images to the Kindle Touch
I won’t go into exorbitant detail on how I did what I did, but this post will pull all the steps together into one place so I have a record of what I did in roughly the order I did it, in case I need to do it again, God forbid. I also throw in a few stray observations along the way.
Jailbreaking the Kindle Touch
“Jailbreaking” is such a harsh word for what Wikipedia more delicately refers to as “privilege escalation.” The Kindle Touch (also referred to as the Kindle 4) has been slower to fall to jailbreaking and custom hacks, but entropy catches up with everything.
In this case, jailbreaking the Touch only opens the door to new capabilties; it doesn’t affect the device’s internals. Jailbreaking opens the door; you still have to install a hack — such as new fonts or custom screensavers — that will take advantage of the opening.
When I first tried jailbreaking the Touch, the process was convoluted and finicky. I gave up after a couple of evenings of frustrating effort. But with the recent Kindle OS update to 5.1.12 (which closed a security hole), an enterprising hacker posted a much simpler procedure. Using the Simple Method and the linked zip file, I installed the jailbreak in only a few minutes. The MobileRead Wiki page hosting those instructions is updated as new/better/more robust methods are developed; there is also a sensible warning at the top of the page that you should read.
I’m not sure, but I believe the jailbreak would prevent any future Kindle OS software updates. Therefore, it would be a good idea to uninstall the screensaver hack and the jailbreak file (in that order) before applying any OS software update.
Because I like my custom images so much, I will probably delay applying any Kindle OS updates until these MobileRead Wiki instructions are updated accordingly.
Installing the screensavers hack
The screensaver hack readme specifies that it will only work with the Kindle Touch without special offers. You wanted to save money by buying the Touch with ads? Then you should be happy with your choice. This hack will not remove or replace the ads with pretty pictures. If you want to see pretty pictures, then you should have bought the Touch without special offers.
Now that that is out of the way…
Programmer and Kindle fan Yifan Lu developed both a simple screensaver hack (zip file hosted on Github) and a custom screensaver hack. I installed the simple screensaver hack; the zip file includes a simple readme with image-naming instructions and an uninstall file.
It’s dead easy to install the simple screensaver hack. Simple connect the Kindle to your computer via the USB cable, drag the file over, unmount the Kindle, unplug the cable, and run Update. Hook the Kindle back up to the computer and you’ll see a screensaver directory with the 20 built-in images. You can safely delete or move these files elsewhere.
Gathering the images
This was the fun part — tooling around the web and looking for images. My Pinboard links to Kindle screensaver sites are a good place to start roaming. Another good place to start would be Google Images: search on “Kindle wallpaper|screensavers”. It’s pretty straightforward to download the images to your computer. Even though some images were clearly themed (such as the Piranesi or Dore images), I dumped all the files into a single directory.
Of course, this phase was also the slogging part — sifting the dreck to find the gold can get tiring. I made zillions of decisions on images in any one browsing session, and simply scanning pages of images meant giving my eyes and brain a break. I spent several evenings browsing Kindle wallpaper sites because — surprise, surprise — I could not bear to leave any site unseen on the off-chance that there was a really great image waiting for me on the next click. Obsessive? Moi?
Formatting the images
Yifan’s screensavers hack specifies that images must conform to the following:
- 600 x 800 pixels in dimension
- PNG format
I’m sure there are instructions out there somewhere on how to convert images from color to gray-scale or on creating gray-scale images from scratch. But I’m not a graphics maven, so I was only concerned with converting existing images to meet these requirements. Fortunately, almost all the screensavers out there are in gray scale; however, they do sometimes vary in dimensions and format.
I used several tools to help blast through this formatting phase:
- Pathfinder 6, a Finder replacement app
- An Automator workflow (saved as a service) that would convert JPG files to PNG files (sorry — no room to explain Automator workflows and services here!)
- Preview, for changing an image’s dimensions and for converting any non-PNG files to PNG
- Keyboard Maestro, for automating the Preview procedure to change an image’s dimensions
So my rough workflow went like this:
- In Pathfinder, use the Edit>Select… dialog to select all JPG files.
- Right-click on the selected files, select Services>Convert to PNG. The Automator workflow takes the JPG files as input, churns away, and creates PNGs with the same filenames in the directory.
- Select all the JPG files again and then move or delete them. So we now have a directory full of PNG files.
- Starting from the top of the file list, use Pathfinder to view each file’s Info and check the dimensions. I used Pathfinder’s drawer for this part, which showed both a preview of the image and its attributes. About two-thirds of the files were in the proper 600×800 format. When I found a file that was not, I selected the file and ran a Keyboard Maestro macro that opened the file in Preview, entered new dimensions of 600×800, and then saved the file.
So, after another few minutes, I had a directory of files in the required format and size.
Grouping and renaming the images
There are two more constraints on image files for the Kindle.
First constraint: The screensavers directory is limited to a maximum of 99 files. I had collected a little over 200.
I decided I wanted a few different sets of files that I could switch out every now and then when I got bored with the current set. So I broke the files into 5 directories of roughly 40 files each. To ensure I had a fairly even, yet somewhat random, collection in each set, I used the Finder’s color labels to help me visually differentiate files into various stacks.
In Pathfinder, starting with the first file, I gave every 5th file a red color. Then green after red, then blue, and so on. I then used Pathfinder’s Edit>Select facility to copy all the red-coded files to a “red” folder, all the blue-coded files to a “blue” directory, and so on.
Great — I now had five groups of files reflecting a mix of styles and images. Not boring!
Second constraint: Filenames. Here’s what the simple screensaver readme has to say about them:
- Each image MUST be named bg_xsmall_ss##.png, where ## is a two digit number from 00 to 99
- You MUST have an image named bg_xsmall_ss00.png and you CANNOT skip a number (ex: bg_xsmall_ss00.png, bg_xsmall_ss02.png but no bg_xsmall_ss01.png)
Pathfinder to the rescue again! A new feature in Pathfinder 6 is a Batch Rename facility that uses an Automator-like workflow interface. I quickly created a renaming workflow for the first group that I could save and re-use for the remaining groups.
If I decide later that I want to instead have larger sets, it’s very easy to move all the files into a single directory and run the renaming workflow again.
Transferring the renamed images to the Kindle Touch
The easiest part! Hook up the Touch to the computer, select and drag the new screensaver files to the Touch’s screensavers directory, unmount, and unplug.
Bah-dah-bing! I now can see a carousel of fun images whenever I put the Touch to sleep.
The above steps did not arrive cleanly and without effort. The process involved lots of trial and error for every phase before I finally hit on the right combination and sequence of steps. You could say that this was an awful lot of work to serve a fairly trivial purpose — and you would be right — but I would say that it was not work: it was good, clean, nerdy fun.