Saving images to mobile gallery

i want to save images to galley of my ionic app. help me to do so.
currently i am using file transfer plugin to do this, but not getting things clearly

I think the documentation is really good with an example:

Maybe you can specialize your question, where you are stuck.

Here you can find a list of file-“destinations” are supported by iOS and Android.
Like iOS the documents folder --> it is synced and crawled by the system.

So for ios you could use:

cordova.file.documents + '/filename.extension' i think

can you see this link, i am using this method but when i run app in browser it show some pop up & after that no screen shows up. even it is not showing developers options…

You are using cordovaFileTransfer --> if you execute the code you will get javascript errors, because this will only work on mobile devices. Connect a device an run ionic run android or ionic run ios to install and start the app on your connected devices (requires for android android sdk, java and for ios xcode)