koobas.hobune.stream
Apk weights 10 times more than assets folder
alt text 
I build a project in 2d with pictures, texts and audio. I compress all the images in my project. But the final apk file is much bigger than all my assets.
If you open the editor log after you build, you will see a list of assets and how much space they take. Then you can find what's taking all the space and target solutions accordingly.
You can also use this utility to get a better visual representation.
Thanks. It really helps. But I still don't know why my pictures with 1068*1600 resolution. In the inspector it weighs 291 kb BUT 
in the log file it is 4.9 $$anonymous$$b. I take the biggest file as an example. the same with the rest.
Unity re-encodes every asset you give it. You should check the import properties for the images in question and the project quality settings. See if you can lower some value without hurting final quality.
It,s probably because you are using a lot of high resolution pictures in your project. I recommend you to change the max size of your pictures. Click on the picture and at the bottom of inspector you can see the max size drop down. If you intend to use the picture as icon then change the max size to 256 or even 128 in other case change it to 1024 or 512. I once reduced more than 100MB from a project just by doing this. It also could be because of audio files which you can't do much about it except using audios with less weight.
