Are these tables concepted correctly?
The unique keys will enforce the requirements you specified, but unless your data entry program either traps error codes returned by MySQL and prompts the user for correction or checks for uniqueness before saving the record, you will probably experience a lot of record rejections where you won't understand why.

I would also use a much larger VARCHAR maximum length for the image_version_e.src column. Remember that VARCHAR columns only require as much storage space as needed for the actual data with trailing spaces stripped (usually). VARCHAR(255) or more is not unreasonable as it will accommodate those really long directory paths or URLs. Your data entry form field for it should be scrollable but much shorter... probably a multiline text field.

See more details in the MySQL documentation of CHAR and VARCHAR.