1- Go to WPML >> Strings Translation
2- Click the link 'Translate texts in admin screens »' (you'll find it at the bottom of the page) 3- Look for an option similar to "theme_mod", or something like that. Here you should find all strings associated with your theme options. You should be able to find the string for mobile/ratina logo
4- Check the checkbox of the string.
5- Click on the button "Apply"(at the bottom of the page)
6- Now, all your selected strings should appear in the String Translation panel and you can translate those strings.
Thanks for your reply! I searched "theme_mod" in String Translation, and I can find 3 related sections. But no string for mobile/retina logo is found. The following 3 screenshots provided you as reference. Thanks!
Twenty Seventeen: hidden link
Parent The7 Theme: hidden link
Child The7 Theme: hidden link