Hi Agrima,
Thanks for the kind words regarding the plugin!
At the moment, the plugin generates a default thumbnail size (which crops the image) so that all of the thumbnails on the front end of the site are unified. Otherwise, image sizes would be all over the place.
You can find the definition inside of timeline-express/classes/class.timeline-express.php
on line #82 :
// Register a new custom image size
add_image_size( 'timeline-express', '350' , '120', true );
I hadn’t considered the possibility for users to use their own custom image sizes. I will look into adding a filter, or some setting allowing you to define your own image sizes.
In regards to increasing the length of the excerpt, you can do so from the Timeline Express settings page. ‘Timeline Express > Settings’. You’ll also want to toggle off the ‘read more’ visibility to prevent users from clicking through to the single post.
Thanks,
Evan