It looks like you are using WP-Juicebox v1.4.2.0 and your images are sourced by NextGEN Gallery.
Please try upgrading to the latest version of WP-Juicebox (v1.4.2.1) which can be downloaded from the plugin's support page here.
Changes were made between v1.4.2.0 and v1.4.2.1 which should hopefully significantly speed up the loading of your NextGEN Gallery images.
You will not need to modify any of your galleries but you will need to ensure that you upgrade the Lite 'jbcore' folder within the plugin's files with your own 'Pro' version. (Instructions for upgrading WP-Juicebox to Juicebox-Pro can also be found on the plugin's support page.)
I do not know if this will solve the problem you report on expanding the gallery but you might like to try setting imagePreloading="NEXT" (in the Pro Options settings window) so that the browser preloads only one image at a time. (The default setting for imagePreloading is PAGE and this preloads all images on the current thumbnail page.)

When JuiceboxBuilder-Pro resizes images, it strips all metadata (EXIF, IPTC, ICC Profiles). If you need to retain metadata in your gallery's images, then the only option is to deselect the 'Resize Images' checkbox and allow JuiceboxBuilder-Pro to copy your original images across to the gallery's 'images' folder.
If you plan to use multi-size images and want to retain metadata, then you will need to create your own sets of images (in an imaging program such as Adobe Photoshop) and replace the ones generated by JuiceboxBuilder-Pro. If you are just creating one or two multi-size image galleries, this might be a possible workaround. As long as you allow JuiceboxBuilder-Pro to create multi-size images (and then replace them with your own images with the same filenames after the gallery has been created), then the smallImageURL and largeImageURL entries will be in place in the gallery's XML file and the functionality will still be there in the gallery.

Try increasing the quality of the images from the default value of 80 to something higher to see if this helps.

If you want more control over the images in your gallery than JuiceboxBuilder-Pro can provide, then you will have to create your images elsewhere and copy them into your gallery folder.

However, please post any suggestions you may have in the Feature Requests thread.
I cannot promise that your suggestions will be incorporated into future versions of Juicebox but it is certainly the best place to post ideas such as these.

It looks like the emulator website you are using may not be giving a true representation of your web pages in the selected devices.
Are you using their Basic or Advanced emulation?
According to their own website, "Advanced emulation allows you to see your websites
like they are rendered in mobile devices.". This suggests that their Basic emulation does not.
It looks like all their Basic emulation is doing is resizing the gallery to the selected device's screen size. However, because this is all it is doing, Juicebox is not detecting the selected device or its actual browser window size so it is not switching to Small Screen Mode (and the gallery is always being displayed in Large Screen Mode).
Try using their Advanced emulation or, if you are already doing so, try a different emulator such as Manymo which may give more accurate results.

I have viewed your gallery on an iOS device and also do not see thumbnails so it looks like your gallery is working as expected (just not in your chosen emulator website).

It looks like the problem may be your iframe's fixed height of 900px. You may need to reduce this in order for your gallery to take up less height on your web page in mobile devices.
Also, your iframe has a height="900px" attribute. This should be just height="900" (although I would recommend that you try reducing the value). The 'px' suffix should be used only if setting the height via CSS.

The Embedding in a Web Template Site support section has now been updated (with instructions for determining the URL to load into the iframe) for the new Google Drive.

The 'Go Back' rollover tooltip text you refer to (which is displayed only when the user hovers over the Back Button) can be changed via the languageList configuration option.
More details on the languageList option can be found here.
This configuration option is not found in JuiceboxBuilder-Pro but you can add it to a gallery by opening the 'config.xml' file in a plain text editor and adding the option as an attribute to the opening <juiceboxgallery> tag.

To change the 'Go Back' text to 'Home', use the following:

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|Home|Buy this Image|Share on Facebook|Share on Twitter|Share on Google+|Share on Pinterest|Share on Tumblr|of"

The opening <juiceboxgallery> tag in your 'config.xml' file might look something like this:

<juiceboxgallery
    galleryTitle="Juicebox-Pro Gallery"
    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|Home|Buy this Image|Share on Facebook|Share on Twitter|Share on Google+|Share on Pinterest|Share on Tumblr|of"
>

A Juicebox gallery can be expanded full-browser or fullscreen (by setting useFullscreenExpand="TRUE").

If you want to disable the Expand Button, then set showExpandButton="FALSE" (in JuiceboxBuilder-Pro's 'Customize -> Lite') section.

If you want to disable the entire Button Bar, then set buttonBarPosition="NONE" (in JuiceboxBuilder-Pro's 'Button Bar' section).

After making any changes, please be sure to clear your browser's cache before reloading your gallery to ensure that your browser is fetching and using the most recent versions of your gallery files.

If you continue to experience difficulties, please post the URL to your gallery so that I can take a look and help further.

You can dynamically create an XML file on-the-fly (at the time the gallery is displayed rather than at the time the gallery is created) using a server-side scripting language such as PHP.
You could use a configUrl within your gallery's embedding code to point towards a PHP file (using a query string to pass any required parameters) and the PHP file would output data in the form of a gallery's XML file.
Please see this forum post to see how this could be achieved.

Thank you for providing the URL to your gallery.
Your purchaseURL contains reserved characters which are currently breaking the syntax of the XML file and need to be escaped. Please see this web page for further details.
Change all & characters in the query string part of your purchaseURL (after the ? character) to &amp; as follows:

purchaseURL="http://www.amazon.in/dp/B00NEFFWF6?pf_rd_p=528846107&pf_rd_s=center-1&pf_rd_t=1401&pf_rd_i=1000826923&pf_rd_m=A1VBAL9TL5WCBF&pf_rd_r=1RQNS2D5ZXCG30PE45M5"

... to:

purchaseURL="http://www.amazon.in/dp/B00NEFFWF6?pf_rd_p=528846107&pf_rd_s=center-1&pf_rd_t=1401&pf_rd_i=1000826923&pf_rd_m=A1VBAL9TL5WCBF&pf_rd_r=1RQNS2D5ZXCG30PE45M5"

It sounds like there may be a syntax error somewhere within your gallery's XML file.
The code you posted looks OK and I have tried it in a test gallery of my own and the gallery displays and functions fine so the error may lie elsewhere.
Try opening your gallery's XML file directly in your browser to see if the browser gives you any indication as to what might be wrong with it.
Otherwise, please post the URL to your gallery so that I can take a look and investigate further.

The SimpleViewer and Juicebox forums both use the same forum software (just different versions which accounts for the slightly different look and color scheme).
After you click on either the "Juicebox-Pro Support" or "Juicebox-Lite Support" forum heading (on this page), the next page displayed (listing all the threads in the chosen forum) has a 'Post new topic' link in the same place as in my original screenshot.
Please take a look at this new screenshot of the Juicebox forum.

It is more than likely that WinZip can be configured to respect the file structure of the archive and create all folders (including the root 'juicebox_pro_1.4.2' folder) so you might like to check your WinZip settings to see if it is set to not create a root folder (or any folders at all).
In any case, I am glad that you have been able to extract the 'juicebox_pro_1.4.2.zip' file successfully and can now install and use JuiceboxBuilder-Pro (following the instructions here).
Thank you for posting back to let me know.

Please see this screenshot which shows where the link is to create a new thread.

If you would like to check that your 'juicebox_pro_1.4.2.zip' file is complete and not corrupt, you can check its file size and MD5 and SHA1 hashes with a program such as HashCalc (free). The zip file should have the following properties.

juicebox_pro_1.4.2.zip
Filesize: 1,731,520 bytes
MD5: d9b0ea9db1be174e3bea5bb678c7a003
SHA1: 0c550f7ab43fb3a2f03d53ad88a93f7fa5df6cbf

If the properties of your downloaded file match those above, then you have the correct and complete Juicebox-Pro package.
It is unlikely but possible that an anti-virus program may be quarantining the contents of the zip file as soon as it is extracted so try temporarily disabling real-time protection in any security software that you have installed.

Also, you could try extracting the zip file using a different program. Both Mac OS and Windows can natively extract zip files but you might like to try a third-party program such as 7-Zip (free).

If the properties of your downloaded file do not match those above, then please try downloading the file again using a different browser (Chrome, Firefox, Internet Explorer, Opera or Safari).

[Post moved to new thread.]

You're welcome! I am glad that your problem has been resolved.
Thank you for posting back to let me know.