Image recommendation engine with Keras

For each manga, I got his picture's URL in the poster's column. I will use the gender columns as a label for my image classifier. But I need to do a little cleaning before because I had 3000 unique labels, I will clean my labels and reduce them. I now have 18 labels and I OneHotEncoded them to have a binary matrix of each label. I have another problem: my label is not balanced, so we will define a class weight that I will pass in my model later.