Photo Stream allows users to automatically sync photos among multiple devices with ease. For some users, automatically importing or uploading photos isn't the preferred method because of privacy concerns.
If you are one of those users who prefer a bit more control, you can turn off automatic uploading of photos you import into iPhoto to Photo Stream, and manually upload the photos of your choosing. It's so simple even a cave...well, you get the point.
If you haven't already, you can turn off automatic uploading to Photo Stream by launching iPhoto and opening Preferences. Select the Photo Stream tab and uncheck the box for Automatic Upload.
Going forward, only the photos you manually select will be placed in your Photo Stream. You can use a photo located anywhere in your iPhoto library. For demonstration purposes, we are using the last imported photo.
Drag and drop the photo over to Photo Stream in the sidebar. You should see a sync icon show up next to Photo Stream as the upload process is taking place.
That's all there is to it, but wait, your photo isn't at the end of your Photo Stream, so where is it? Well, the photo(s) you upload to Photo Stream are sorted by the date it was created, and not the date it was uploaded.
As you can see in the screenshot above, the photo we imported was placed in the middle of the stream. So if you can't locate the photo right away, scroll through your stream to the time frame it was created, it should be there.