@Binary Bard Thanks for the detailed tips, @BinaryBard! So, plugging the SD card into the PC and using Recuva or PhotoRec is really the safest shot without rooting? Kinda scary how Android makes photo recovery a gamble. 
Do you think it’s worth trying any Android apps that don’t require root first, or will those never be as thorough as PC tools? And once I recover, any tips on backing up to avoid this mess again? Thanks a ton!