Clicking on the image on an already-open slideshow breaks #1695's fix for images having different widths after the modal is closed

[benlk]

Given a single image in an image block that is aligned left or right, take the following steps to reproduce this bug:

1. Click/tap on the image to open the image in a Navis modal.
   1. the modal opens
   2. The image width is set to 100%: https://github.com/INN/largo/blob/e2ac830239452658c285860b330d521c6a0f300e/lib/navis-slideshows/js/navis-slideshows.js#L271
2. Click/tap on the image in the Navis modal.
   1. Nothing happens that the user can see, but the function addCloseX is called again, adding a duplicate X in the modal (which is invisible to the user because it's stacked atop the current X, using the same CSS rules for positioning)
   2. The 100% image width is saved as the pre-click image attribute https://github.com/INN/largo/blob/e2ac830239452658c285860b330d521c6a0f300e/lib/navis-slideshows/js/navis-slideshows.js#L263-L268 and is now relayed to the event handler that calls closeSingle https://github.com/INN/largo/blob/e2ac830239452658c285860b330d521c6a0f300e/lib/navis-slideshows/js/navis-slideshows.js#L274-L276
3. Click on the X to exit the modal.
   1. The 100% from the second click is used as the pre-click image width by closeSingle when the image is closed: https://github.com/INN/largo/blob/e2ac830239452658c285860b330d521c6a0f300e/lib/navis-slideshows/js/navis-slideshows.js#L177
4. The image is now 100% of the column width rather than its previous appearance.

So the questions I have are:

• is there a way to remove that 100% image style setting, and just put it in one of the CSS classes applied to the image, perhaps as a !important?
• is there a JS sibling selector that we can run on the img to check that it doesn't have a .navis-before class as its sibling, which would mean that the dialog has been opened? We'd want to apply that here:

https://github.com/INN/largo/blob/e2ac830239452658c285860b330d521c6a0f300e/lib/navis-slideshows/js/navis-slideshows.js#L254-L255