Problems Scribes Didn't Have - Or Did They

I was recently looking at a comment about my website Medieval Writing on a bulletin board. I don't do this for vanity, but for quality control! A user was recommending certain pages as useful for learning to read a particular medieval script, but complained that the images of the letters were highly compressed and contained artifacts. Of course, my initial response was to harrumph mightily, but it is true.
The problem is that what I see on my browser on my computer may not be exactly what another user sees using different hardware, and what is an acceptable download speed for graphics on one connection might be utterly impossible on another. When I first started the website, I had a slow dialup modem connection, as did most people especially at home, and I based my benchmarks around that. I have also recently upgraded my vintage Windows 98 computer with CRT screen for a new laptop with a hi-res flat screen, and crikey, does that make a difference to how the graphics look. Images on the old CRT screen have a tendency to be warm and fuzzy, and I was forever trying to sharpen them up. Images on my new screen are cold and crisp, with a tendency to be jaggy and full of inexplicable dots and squiggles if they have been optimised for the other screen.
Now, do I assume that everybody these days has a broadband connection and a modern screen, or do I still have to cater for the dial-up connections and the old computers? I guess it just has to be a compromise. I have been castigated by users for not catering for Linux users or optimising for all the different browsers in existence. Some major upgrades have been made to the site in the past to resolve some anomalies, and if I had the resources of, say, the tax office, I could get my IT minions to produce a version for everybody, and an automatic detection system to steer each user into the right version, but I'm afraid that medieval paleography just doesn't have the same resources as tax collection, especially when you're trying to keep it free.
The only consolation is that if the users of the site are going to practise their skills on real medieval documents, they will find that the letters in those documents are as uneven, jaggy and as full of artifacts as any jpeg. Scribes didn't actually write using model alphabets. And they had problems with their technology. Sometimes the writing turns really nasty when the scribe has changed his pen and the new one just won't flow properly. He just had to re-cut his quill- no help desk!