The fact that the format is lossless does not mean that the path by which it got into that format wasn’t lossy. This is particularly likely if your image is hosted on an external service. There is a limit to how well a lossless algorithm can compress, and so a pre-compression step helps them reduce the size of the image.
I would therefore second your suggestion of storing them in an external service of some kind.
I will try asking to see if I can attach a .pdf first, but if that fails it looks like I will take all of your advice and try to share/host it somewhere else.
Regarding the map, it looks like this final step may take me a little more time than I hoped. I originally planned on a day or two, but my penmanship is worse than I anticipated. Who knew not needing to write anything legibly for a long time would ruin my ability to write! Maybe don’t expect much from me for a week or two.
Also, here is the quote I am working from (in chapter 54):
Finally, he set down his drink and pushed some clutter to the side of his desk, revealing a large map of Gilbratha with different colored zones, arrows, and notes scribbled all over it.
The colored zones I am imagining as the gang territories, and maybe the Oliver Dryden Vs Lord Stag interests. The arrows are my weakest category, right now I only have police/enforcer patrol routes? And the notes are only limited by my own penmanship, but could be important opportunities for expanding Verdant Stag influence, or stuff about the other gangs I guess?
My List of Stuff:
Gang territories
Oliver Dryden Properties
Verdant Stag Interests
Other
Off the Map (where to note?)
Feel free to let me know if there is anything else anyone wants to see.
Oh, oh, I have an idea of where to post it!
Give me a bit to double check before I drop link, will prob make a whole new thread!!!
This is amazing! People have been interested in a more expansive map for a while, but it is a big project (as you know) and I haven’t had time to work on it myself. I love what you’ve done.
I am going to DM you about a possible collaboration. 
In this instance, if it were possible to post the file as the original vector drawing, it would genuinely be “lossless” And, proabably a smaller file besides. Adobe .pdf allows for vector drawing in that format, as well as a others file formats. But, that does not necessarily mean that the vector-based software is allowing it to retain the vectors on export.
I love my “Graphic” drawing software on iPad, but it can be very frustrating to share with others.
It does not look like I will be able to post a .pdf directly right now, so I will move on to try and figure out how to host it somewhere, probably this weekend sometime.
I was going to try google drive or something first, but if that does not work out, I will look into the site. I might have heard of it but I am not familiar with it.
Thanks, this is nice to hear! I feel like I should say that I have only been able to do this much so far because the story conveyed a very compelling, strong image for the city (and for the world, even if we have only seen Gilbratha so far!). Thank you for that!
The .pdf I can create does preserve the vectors, but the fills/hatches/shapes get subdivided into triangles and other geometric shapes at the whims of the computer. So although the basic linework should be easy enough to edit, any bigger changes may get a bit tedious.
I may have spoken too soon? If this works there should be a .pdf here!
Gilbratha-3-7-24x36.pdf (786.8 KB)
IT WORKS!!! I’m checking it out now. This is amazing!