The images that you have on the LR Mobile, are they synced from LR Desktop or are they from Camera Roll.
If they are from LR Desktop then the images do not take much space as they only the thumbnails that are created.
Also please check on your iPad that which app is consuming the most space: https://support.apple.com/en-in/HT201656
Please let us know if it helps.
It is not the images that are taking 26 Gb of your disk space, it is the total amount of memory that has been used on your phone.
So, I would suggest to please check once which app is consuming the most space .
Please go to the following link and it will help in checking the disk space : https://support.apple.com/en-in/HT201656
Okej, now I understand! Now I free some space, by throw away some program and stuff. Problem solved!