I need to add custom icons in my tab. Suppose for home tab i need to include home image. Can we include custom icons in tabs that will be included in Packages?
Yes this is possible.
You need to upload your graphic as a Document in a Folder of your choosing, ensure you add this to your package. Then when you edit your Tab, you can click the "Create your own style" button to choose this image and tab style (or choose then to upload at this time). This topic in the help describes the process in more detail. Keep in mind the following restriction when choosing images for tabs...
This dialog only lists files in document folders that are under 20 KB and have the Externally Available checkbox selected in the document property settings.
NOTE: I've not been able to find a statement in the docs regarding the dimensions of the image, however I did find a post from the oracle that is Bob Buzzard here, stating that following Salesforces own 32x32 dimensions is a good starting point.