Hi Mark,
I've added a *test* feature 'retina' (and by 'test' I mean, it's outside the scope of the original easymap shim, so if it breaks something, or otherwise causes trouble I will need to remove it, so please don't rely on it just yet for anything mission critical, but do feel free to test it and feedback any issues).
The retina value can be either 1 or 2):
Setting it to 1 will do nothing (and is the default, so no need to include it).
Setting it to 2 will double the resolution of the returned image.
e.g.
https://easymap.nbnatlas.org/Image?tvk=NBNSYS0000005108&w=790
Image will be 790 pixels wide.
https://easymap.nbnatlas.org/Image?tvk=NBNSYS0000005108&w=790&retina=2
Image will be 1580 pixels wide.
The w parameter itself is still clamped to 800.
So we'll have to see if works ok, but it shouldn't effect existing urls.
Atb, -Duncan.