Accessing an SD Card on different shield?

Development Boards Arduino
1

I’m trying to put together prototype that can play audio and display images transmitted via wifi from a mobile device.

Before I purchase a lot of modules that might not work together, I want to find out if anyone has tried to to use multiple shields that each have their own SD Card slots (for example, The Sparkfun MP3 Player Shield and the Serial Miniature LCD module), and stored data in those SD cards from another shield.

The specific use case would be this: the sketch receives an image over wifi, can it save it to SD card slot on the Serial Miniature LCD module, or does it have to save it to an SD card slot connected directly to the Arduino. Secondarily, if an audio clip was received over wifi and saved to the SD card slot on the Serial Miniature LCD module, could that audio clip be accessed directly by The Sparkfun MP3 Player Shield.

A last question would be, is there a better way to mix shields that require access to external storage?

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What kind of image are we talking about? If it’s a black and white that’s 840x640 or smaller, than an Arduino could handle it, but if it’s a full size color image, than Arduino will not be able to do anything with it. It’s not the lack of power, it’s how large the image is taking up memory. Before an image can be transferred to an SD card, it has to be put in memory.

if an audio clip was received over wifi and saved to the SD card slot on the Serial Miniature LCD module, could that audio clip be accessed directly by The Sparkfun MP3 Player Shield.

As long as the clip is saved to the SD card for the player, I don’t see why not. The problem would be getting it to the SD card in the first place. Over the years, I have not heard of anyone saving files to an SD card (MP3 Player) while it’s still in the shield. From my knowledge, the circuit would need more components to do this function.