Hello, @theeventscoy,
First of all, yes, the htaccess file needs to be edited, so that the image requests can be filtered by the Adaptive Images plugin and thus be handled accordingly, ie the images be resized per screen size, etc.
Now the plugin does this automatically for Apache (and compatible) servers in the usual case where the htaccess file is editable by the server user. If this cannot happen automatically then you need to do it by hand. But you will get a special message for this when you save your plugin settings in the /wp-admin.
Nginx does not allow this automation in any case, so you do need to edit its conf file manually. Again, you will see a special message for this when you save your plugin settings in the /wp-admin that mentions what you need to add to the Nginx conf file. Unfortunately, you may need to tweak that bit of code a little bit depending on the specifics of your installation.
Hope that helps!
Cheers,
Takis
