Sam Biddle's "The Slides"

Sam Biddle has collected, scanned, and curated a large number of slides. "The slides appear to be 1970s/1980s informational or training images from the United States Air Force, NORAD, Navy, and beyond." You can visit Sam's site dedicated to these slides at sambiddle.com, and download the slides themselves via his account at the Internet Archive.

This Python suite posts The Slides to Bluesky, four times a day, at the account theslides.bsky.social.

Dependencies

This project relies on:

• Pillow to process the original slide scans into tinier, more-uploadable sizes
• requests for communicating with BlueSky

They can be installed with these commands:

$ pip install --upgrade Pillow
$ pip install requests

Here's what the virtualenv I have on my laptop looks like overall (Nov 23, 2023):

$ pip freeze
certifi==2023.11.17
charset-normalizer==3.3.2
idna==3.5
Pillow==10.1.0
requests==2.31.0
urllib3==2.1.0

Additionally, in my Windows-Subsystem-for-Linux, I had to install Tkinter to make add_alt_text.py work:

$ sudo apt-get install python3-tk

shrink_images.py: Reprocessing originals

I have downloaded, just manually, via browser, the slide collections in JPEG format, as available on the Internet Archive (link above). The first nine were downloaded on Nov 23, 2023, and the next five on Jan 29, 2025, and match the galleries available on Sam's site. Altogether, they come to 422 images of total size 1.5 GB. Their typical resolution was around 5,550 pixels wide by 3,500 pixels tall.

I reprocess these images to a width of 600 pixels, since that seems to be just a bit wider than the photos you see in your BlueSky timeline.

I've organized these originals in directories with names corresponding to the names Sam gave the collections. The only weird part is I did some minor substitutions to make them feel more like real directory names -- no whitespace, no punctuation. This just means that '_' in a directory name means "a space" in the actual collection name, while '__' means "a comma, then a space." Capitalization & casing are kept constant. So the directory SERIES_78__AERO_SPACE_DEFENSE_COMMAND_BOX_1_OF_2_V-0092 maps to its collection name "SERIES 78, AERO SPACE DEFENSE COMMAND BOX 1 OF 2 V-0092". This matters because I want to include the original collection name in the text of the BlueSky post, and these directories are the only way I save those names.

The shrunken images are serialized as JPEGs, and their Base64-encoded bytes are stored in a SQLite table named slides with the following columns, all of type text or integer:

• collection: The name of the slide deck the image comes from
• filename: The actual filename of the image
• file_id_num: An index for the file within its collection, like the "7" in "Image 7 of 20"
• jpeg_base64: Base64 encoding of the 600-pixel-wide version of the image
• width, height: Dimensions of the image

You can check this worked OK with test_db.py: that the collection names are all recognized as linkable back to Biddle's galleries, and that the base-64 strings really can be parsed into JPEGs again.

slide_viewer.py and add_alt_text.py: Add alt text to images one-by-one

A workflow for adding alt text is:

(1) View the slide you want to annotate with slide_viewer

Identify your slide by its row ID in the table slides in the above sqlite3 file. View it -- as in, the actual jpeg stored in that row -- with this command:

$ python3 slide_viewer.py slides_db.db3 id:1234

That id: prefix is load-bearing and if you don't include it, the job fails. You have now confirmed that you're about the annotate the right slide.

If you don't have a particular slide in mind, you can omit the row ID argument, and the script will (try to) pull up an image that lacks alt text. Like if you want to increase alt text coverage and you don't care which image gets it first.

(2) Write the alt text to a local text file

Save the desired alt text, line breaks and all, into any local text file. I'd use /tmp/alt_1234.txt for this example.

(3) Update the database with add_alt_text

Move the alt text from the text file of step 2 into the row you viewed in step 1 with the command:

$ python3 add_alt_text.py slides_db.db3 id:1234 /tmp/alt_1234.txt

Note that the alt text filename is not parsed for the sake of any business logic beyond "open this file and slurp up the contents." The fact that it has the rowid in it, in this example, is just about human bookkeeping. Only the id:1234 argument is used to identify the right image row to update.

post_image.py: Post a processed slide to BlueSky

You supply login credentials with a text file of this wacky custom format, with these specific keys pointing to your own particular values:

ATP_HOST = [your host, very likely to be https://bsky.social]
ATP_USERNAME = [your username; like, right now, I'm using theslides.bsky.social]
ATP_PASSWORD = [an app password for this account]

To be clear: everything outside the square brackets needs to appear in this credentials file verbatim.

The script then connects to, and extracts an image and its metadata from, the SQLite file created by shrink_images.py. It reports the name of the collection the slide comes from, as well as a "slide X of Y" designation based on the sort-order of the filename of the slide within its collection.