Fixes #791 Update texts related to WebP and Next-Gen

[Tabrisrp]

Description

Update some strings that were missed or not updated correctly.

Fixes #791

Type of change

• Bug fix (non-breaking change which fixes an issue).

Checklists

Generic development checklist

• [x] My code follows the style guidelines of this project, with adapted comments and without new warnings.

Test summary

• [x] I triggered all changed lines of code at least once without new errors/warnings/notices.

[Mai-Saad]

text is updated in mentioned areas now. if nothing is needed to failed tests above then we can merge this one