Google Image Downloader, sometimes called Google Gallery is actually a software application. This software application is available for free on the internet. If you want to use this software then you have to download it from the relevant websites and install it. The application does not require any kind of installation. Once you have installed the software on your system you just need to click on the option 'get help' if you find problems with this software.
Google Image Downloader looks like a simple application which will help you to download images directly from Google. The main screen shows the following interface: you will get to see the different categories under which the images are available; you will get to see the download button and you will also get to see the size of the images in megabytes. If you click on the button 'download images', the software will ask you to browse through the list of folders in which the images are available and you can choose any of the images which you want to download. However, there are certain limitations of the software. The main limitation is that you cannot download all the images from all the places like the news, forums, etc.
You might be asking as to why there is such a big difference between Google Image Downloader which is a free software, and Google gallery which is a paid app. As the software has been designed for the Windows operating system only, the files are compatible only with the Windows version of Google. Similarly the paid app has been designed only for the Windows 10 operating system. In case you are using the software to edit or share the images from a different platform like the iPhone, you will not be able to use the application. To conclude, the Google Image Downloader does work but the free gallery application is more convenient and allows you to save your favorite pictures easily.