The RP2040 has 264KB of SRAM, and I’m using a 24Kb gif, if it can’t handle that, this may be all for naught.
I changed the PIN that SD uses (Seeed documents the SD card slot uses D2, D8, D9, D10). Hardware Usage | Seeed Studio Wiki
I don’t get the “INSERT SD” error using other pins, but the board also ceases to function after the SD timeout happens.