I have been trying to add a png image from the library to a fluid box that already contains one image. Instead of adding the image and resizing both images, this move overwrites the original image with the new image. If I want to get the desired result, I have to drag the image from the library to another (empty) fluid box and then drag it into the desired fluid box. I feel like I'm missing something really simple, but I don't know what. Please help.
Which exact version number do you use? I try to understand, and suspect you are suffering from a feature which I would like to be able to turn off: the automatic replacement of an image. Maybe another suggestion: duplicate the first image with CTRL-D and drag the new image over the duplicate. Annoying but easier than using another fluid box.
If the first image is not filling the Fluid Box, try this workflow: select the fluid box, and drag the new image to a non-filled space. That helps me to avoid the automatic replace feature.
Third workaround: change the FB to static, drag second image (will probably stack with first) and turn off Static again.
I am currently using Adobe Captivate 2019 22.214.171.1243. CTRL+D and draging the image still replaces the image. The second suggestion is what I'm currently doing now. I've watched videos produced by adobe (specifically Dr. Pooja Jaisingh) where the instructor is able to just drag and drop the image into a fluid box and add it rather than replace it. She did it with and without the FB being static.
I am on the same release and I did check all the solutions I proposed. They worked for me even with CTRL-D if you drag the new image really only over the duplicate. Maybe you can ask Pooja? Did you ever see it being done 'live', not in a video but in a webinar?