It certainly sounds like there might be a problem with certain images and, when JuiceboxBuilder-Lite chokes on them, the publishing process grinds to a halt, resulting in an incomplete gallery folder.
If you could upload the images that you are having trouble with (so that I can download them and use them in a test gallery), I'll certainly take a look to see if I can replicate the issue (and maybe find the root of the problem).
... no matter what I tried I could not load the sixth, not as .jpg, .png nor .gif.
It seems very strange that you have re-saved the image in different formats and JuiceboxBuilder-Lite rejects them all.
Normally, if an image is corrupt, the best thing to do is find an imaging program that can open it and then just re-save it (without making any changes to it). The process of re-saving the image can sometimes fix any problems with it.
First of all the .tempGallery problem seems to have gone away.
That's good to hear. Thank you for letting me know.
I notice that your image filenames are very long. The 4th image in your 1st gallery, for example, has 194 characters in it (not counting the file extension).
When working with these files on your computer, you might be reaching the Windows maximum path length (MAX_PATH) of 260 characters. Please see this Microsoft web page for details.
If your image is in your 'Pictures' folder (for example), then this could add approximately 20 characters to the path length (depending on your user account name) but if your images are stored in a deeper file structure, then you could quite easily be pushing the 260 character limit and this might be causing problems.
I would recommend that you reduce the number of characters in your image filenames to see if this helps with your problems.
Incidentally, as noted in the web page I quoted above:
Starting in Windows 10, version 1607, MAX_PATH limitations have been removed from common Win32 file and directory functions. However, you must opt-in to the new behavior.
I hadn't made any changes to the four images displayed previously, but as well as the fifth not showing online the fourth has disappeared.
The 4th image has not really disappeared. Your 'Test-5' gallery seems to be an incomplete copy of your 'Test-4' gallery. Your 'Test-5' gallery uses its own set of images (its own 'images' folder) completely independent of the images being used for your 'Test-4' gallery.)
In your 'Test-5' gallery, the 4th image does not appear to be present in your gallery's 'images' folder.
According to your gallery's 'config.xml' file, the 4th image should be located here:
http://www.sirnigelgresley.org.uk/PhotoArchive/Test-5/images/Peter Lane - 4498 on a photo run-through at Appleby on 25th September 1993. Cumbrian Mountain Express with headboard The New Inn Farewell. Photograph taken from far north end of station platform.jpg
... but going directly to that location in a web browser (taking Juicebox-Lite out of the equation) results in an error 404 (file not found).
Please double-check that the image is present in the correct folder on your web server.
The 5th image in your 'Test-5' gallery gives a different error when trying to view it directly in a web browser.
The document name you requested (/PhotoArchive/Test-5/images/Peter Lane - 4498 at Newcastle on 6th June 1985 awaiting departure Carlisle. Thames â€“ Eden Express.jpg) could not be found on this server. However, we found documents with names similar to the one you requested.
/PhotoArchive/Test-5/images/Peter Lane - 4498 at Newcastle on 6th June 1985 awaiting departure Carlisle. Thames – Eden Express.jpg (common basename)
This seems to be due to the use of the '–' character in the image filename. This is not just a regular hyphen '-' but a special character that seems to be encoded as 'â€“' on your web server.
As an image filename forms part of a URL when uploaded to a web server, it would be wise to use only web-safe characters within image filenames. Please see section 2.3 of this document for details.
Characters that are allowed in a URI but do not have a reserved purpose are called unreserved. These include uppercase and lowercase letters, decimal digits, hyphen, period, underscore, and tilde.
I would recommend using only the characters noted in the quote above for your image filenames (and not other characters such as spaces, '&' and '–'). (JuiceboxBuilder-Lite can handle all images whose filenames use any or all of these unreserved characters.)
Using shorter, web-safe image filenames might help to solve your problems (both on your computer and on your web server).
I hope this helps.
I was typing my reply whilst you posted your last response.
I'm glad that you've been able to figure out the cause of your problem. Thank you for letting me know.
Hopefully my notes above will give a little more information on the nature of the problem.
Please let me know if you're unable to resolve your issue with the blank thumbnail (let me know which gallery you are referring to) and I'll take a look to see if I can help further.