Hi again
That's natural because the width calculation method for each modules. Depending on number of modules displayed in a row they will have a specific width. So the best solution is to increase image size in a way that it will fill completely the module content div.
The other way is to add an rule on template parameters > Layout > Template modules blocks, by setting higher width value for specific module and therefore the rest of modules will have lower but equal width.
In other words, it's using the width of one module to adjust automatic the other in same row.
Cheers