I created an object style to apply to pasted images in my document. The object style has a 6 point white stroke. I then applied this object style to two images and the size of the stroke is visually different.
I'm not resizing the images after applying the stroke. This is the result of applying the style after sizing the images.
This is a visual representation of my problem:
How can the same weight stroke be a different size?
You probably scaled the image using the "object selection tool" (black arrow, direct selection) rather than the "object content tool" (white arrow, direct selection).
If you scale the image using the direct selection tool and then size the box to the proper crop, the contents of the box are scaled rather than the box object itself, and the object styles remain as expected.
If you scale the entire object, the styles applied to it are scaled as well.
As a side note, this subtle difference is a source of frustration for me with ID user interface: when an object is selected and you want to switch tools in order to switch context to avoid issues such as you are experiencing, you must deselect and reselect the object (the tool switch happens, but the context does not change). Additionally, you need to switch tools again to manually resize the box after you have scaled the content and want to bring the box size in line with the new size.
I agree it's very confusing to try to keep track of which transformation methods affect object styling. Most of my woes have been resolved by utilizing one or both of these options depending on the situation (these are in InDesign CS6)
Transform Pallette - Strokes option
Turning this off before scaling your object should make it so any styles applied to it are actual and not scaled.
Style Overrides
Select the object you are styling, if you notice a little + following your style name in the Object Pallette (or other applicable style pallette such as Paragraph Styles), it means some additional transformation has overridden one or more of the settings that was originally defined within the style settings. Alt/Option clicking the style will force the styles back down on the object clearing any overrides. In your case, this should revert the style back to the defined 6pt stroke width regardless of any scaling that has been applied to the object.
As you can see, if you hover over the style name, the pop-up even displays the overrides that are active on the selected object.
You can also use the transform pallet to 'Redefine Scaling as 100%', this will change the stroke weight to reflect the true weight (not the scaled weight) so all you need to do then is re-apply the object style or manually change the stroke weight in the stroke pallet so stroke weights are the same. I'm really bad at explaining this stuff, sorry, have a play and hopefully you'll get what i'm on about.
