mapState = (state) => ({
    images: state.images, 
    compression: state.compression
})
NOTES
    - multiple files can be selected at most 15.
    - If 10 files already dropped and user trying the drop the new files, then give error.
    - User can remove any files from the dropzone before uploading.
    - Compression Button should be disabled before any file dropped.
    - Give error if user select any file greater than 12 MB and exclude from list.
    - If user select the same file twice, exclude it.