Good morning,
I have the Alloy or all the stacks from you.
Now I have asked myself whether it is feasible if I write posts in my blog that the images (contribution images) can always be displayed in the right size without having to resize the image every time. Do you have an idea 
Thanks for the help
You must resize your images to the size you wish them to be before uploading. This is true of all images for your site. This is so that you’re only serving up the amount of data necessary and no more. This allows for faster load times and an optimized experience for your visitors.
Additionally you should always be compressing your images before uploading or placing them in your site, so you can do both things at the same time.
Also let me add, for “handling” images you could use Graphic Converter, a very advanced image app (I have no benefit for writing this from GC, except that) it is superb.
