For my ancestry research, I want to create a local backup of the online sources (which are free and publicly available), like here: https://ebadatelna.soapraha.cz/d/6657/5

Using right click -> download image, or the sniffer, I can download any individual page. My issues start when I want to download more than one image at a time using the manager.
1. Through the sniffer I found the image URL, like this one: https://ebadatelna.soapraha.cz/wicket/resource/org.apache.wicket.Application/Kolesovice_01__001.jpg
For the remaining pages, the number at the end increases to 002, 003 etc., I also validated this through the sniffer.
2. Using a spreadsheet, I created a list of all images I want to download from that particular souce.
3. When I copy+paste the list into the chrono download manager, it will only download the first image (if at all). From the second link onwards, all the links in the tasks will somehow auto change from a .jpg ending to a .htm ending.
4. Using the chrono download manager, it would only download the pages 001 or 002, if I tried downloading any other links, they would fail by default.

Is there any fix to solve this? Again, using the sniffer, I can download any individual image without any issue. Or is it the website that somehow blocks the bulk download?