The Splash Page's "View Gallery" text can be changed via Juicebox-Pro's splashButtonText configuration option (in JuiceboxBuilder-Pro's 'Customize -> Splash Page' section).

The "Images" text (in "X Images") can be changed via the languageList configuration option.
More information on languageList can be found here.

languageList is not featured in the JuiceboxBuilder-Pro interface but you can set the option manually in the gallery's XML file or JavaScript embedding code by following the instructions here.

Change the 6th entry in the list ("Images"):

languageList=""Show Thumbnails|Hide Thumbnails|Expand Gallery|Close Gallery|Open Image in New Window|Images|Next Image|Previous Image|Play Audio|Pause Audio|Show Information|Hide Information|Start AutoPlay|Stop AutoPlay|AutoPlay ON|AutoPlay OFF|Go Back|Buy this Image|Share on Facebook|Share on Twitter|Share on Google+|Share on Pinterest|Share on Tumblr|of""

If you wanted to, you could switch off the "X Images" text by setting showSplashImageCount="FALSE".