I think those conditions are generic for all the images available on that site.
You can download the images from other sites, even other ESA sites do not have those conditions. The Planetary Science Archive, for example, only says:
Please acknowledge the above Principal Investigators as well as the European Space Agency when making Back to FTP Browser a publication using the data you are going to download.
So, you can download the image from here, just select "High Resolution Stereo Camera (HRSC)" and acknowledge the principal investigator, G. Neukum (Freie Universität, Berlin, Germany).
You can use the browse (JPG) versions of the images or the original data (IMG) versions, but for these you will need a program capable of reading those files, ask me for more information if you want to know about it.








