How to annotate complete images?

I am currently playing around with tensorflows object detection to learn the basics.

Now I've set myself the goal to detect letters in computer written text. For example the header of a newspaper article.

I know that object detection might not be the way to go for letter detection but I wanted to know how well a object detection model performes when input data is perfectly similar( computer generated fonts).

My Question:

I encountered the problem that manually annotating each letter in given headers is a really fiddly job and feels not good for training a model.

Now I ask myself this: I could write an Adobe script to generate me an image for every letter of a font(or multiple fonts) with different backgrounds and rotation and save it to my filesystem. - this would result in (10 Fonts * 256 characters * 10 backgrounds * angles) 256000 images for model training.

For training purposes this is a great amount of data but if I want to annotate each image myself it will get nifty especially because each 1000 images have the same tag..

Question 1:

Is there a package or tool which annotates the complete image with a given tag?

Question 2:

Will training a object detection model with cropped images even work or is a rational approach?

Every help/suggestion is highly appreciated! Thanks in advance :)