What I understand, for one single image you want to create copy of that image with different sizes. Is that correct?
There are two approaches to perform this:
- Use TBB to resize the images and include those in package.
- Use event system which will create resized copies of images based on the criteria you decide on save of the component. Then you will have to write it in TBB to include those different sized images.
Since you have performance concern with 1st approach, you can choose for 2nd option. Please note, if you are using event system then it will be performance hit on CME.
So either way you will have performance impact either on CME or on Publishing. You have to choose which one fits your requirement and helps you long term.