Is it necessary to have SDL mobile installed for DXA 1.2 context image delivery to work correctly ? If I don't want to avail paid service of SDL mobile what are the different alternatives ?
here's what docs say-
default Context Engine Cartridge installed as part of
SDL Digital Experience Accelerator is used to detect device/browser screen features and capabilities.
-This information is used to manipulate page layout and image resizing and drive a reponsive design.
-This functionality is free to use without an SDL Mobile license, however if you do have an SDL Mobile license, you can take advantage of some additional features;
First request device capability detection and
Contextual Image Delivery.
Read more at docs :Setting up Context Engine Cartridge (SDL Mobile) , hope it will clarify most of the questions.
Related information is present on some other posts on
StackExchange already,see this for ex- https://tridion.stackexchange.com/a/12887/1449