Is the application will take our data for them? I.e: It ask to access images in the phone, will the application will copy and send all the images to the developer? Or, will the application copy the conversation as it has access to the microphone?
However, a malicious actor would naturally want to have access to all the private data of yours, so their app may listen to your private conversations, use your camera, upload your photos and so on once you have granted access to the permissions it would have demanded.
Some detection and preventive safeguards can be deployed, but that matter is beyond the scope of this question here.
And how long it will have the access one we granted and installed the application?
Since Marshmallow, a user can revoke or grant certain dangerous permissions later in time even if they had been granted earlier, by going into Settings > Apps. The permissions stay as long as the app stays in the device. Once you uninstall an app, all granted accesses are lost, but not the data that it may have collected and uploaded somewhere else. A reinstallation is no different than a fresh installation in terms of permissions access.