we are using 5G disk space. This data amount makes it really slow to push staging to live. we think there are tons of non-used images and other logs we can remove. is it correct?
Hi @Jady_Yarcoo and welcome to Kinsta Community!
Removing old images is definitely a way to save some space, you can also manually resize those so that are compressed. There are some plugins that can also scan your current Media library and the images found inside the /wp-content/uploads folder but those will need to be used very carefully and making a backup of the data is very recommended. An example can be this plugin, before you give it a try though, again be sure to make a backup 
Regards,
Alessandro