As I understand it - Google Image Labeler only allows you to label random images from the internet (not specifically pick your own images) - so you could spend approx 2237 years doing this!
With regards to image bot being SLOW - in my experience that is true and there is NO way to speed it up (someone correct me if they know better). It normally takes at least 3 months to get new images on my site
Ireland Photos / Desktop Backgrounds / Irish Wallpaper to appear in Google images..
In my opinion - it also helps if your images are very good quality - e.g. if more people click on your image for a specific query than anyone elses, it tends to rise towards the top of the image search results (again is anyone knows better, please correct me).
It also helps if you allow others to link to your images, and then politely request that they link back to your web site if their site starts appearing in the image results...
I don't think you need to resort to H tags.
I have a feeling that images from your site may tend not to turn up in the Google Image results if 'Safe Search' is turned on (which it will be for the majority of users who do not know how to change the image search settings)..