Translation:The image is too big for my screen.
This is another example of how DL giving a little explanation would go a long way in the learning process.
I was marked correct for "The image is very big for my screen".
If I did not check the discussion, I would have never known that "muy" can be used in this way.
Agreed. Sometimes there is a gem of explanation in these notes, sometimes some good humour, but often a lot of confusion. I have to be careful I don't spend more time looking through them than actually doing exercises. In this case I was wondering how an image can be too big for a screen, since these days the software resizes them to fit and you wouldn't even know...
Muy = very, too, greatly, or highly
"The image is very big for my screen." Accepted 9/21/2019. "This image is very big for my screen." - I haven't tried yet (I will try next time, just to confirm), but 'this' is not usually interchangeable with 'the'. "The image is too big for my screen." -Given answer, and most correct sounding, if not at first when the 'muy = too' is still new. I think to this point on DL I may have only seen one other use of muy like this, maybe not even that. I'll keep this usage in mind in later exercises, when it may seem more appropriate than 'muy = very'.
That's a little different description of the image and a little different construction in Spanish. To say something is too big for something else is not the same as saying it is bigger. A sofa that is too big to comfortably fit a room is very likely smaller than the room. Likewise, an image described as too big for a given screen may not necessarily be bigger than that screen. It certainly may be bigger, but the Spanish sentence does not guarantee that.
If the Spanish sentence was closer to La imagen es más grande que mi pantalla, then your translation would be perfect.
No. that would be "más grande que" rather than "muy grande para." It may mean the same thing in some contexts, but not all. I'm really not arguing there's a huge practical difference. I'm just suggesting they are not completely interchangeable statements and each aligns with a different Spanish phrase.