fix path to thumbnail images incorrect on second and higher page

[kartnico]

Merge Request for this bug : 427

Pull Request type

Please check the type of change your PR introduces:

• [X] Bug-fix
• [ ] Feature (functionality, design, translations, etc.)
• [ ] Documentation change
• [ ] Project management (tests, CI, GitHub configuration, etc.)
• [ ] Other (please describe):

Current state

Issue Number(s): 427