Arduino UNO + OV7670 camera FIFO + SD module

hi, i have a problem with the final result of the photo.
i can take the photo(i convert the yuv image using ffmpeg to png format), but it looks bad, like gray with green spots.
the registers should be well, i compare the registers from a book about the camera and arduino Mega,
and also from a topic of this forum:

so i have no much idea what the problem is,
i even think it’s because of the wires.i can’t get some more wires(quarantine).
or maybe because i use a SPI bus, there’s two slaves, the sd card module and a shift register, i know the shif register 74hc595 has a tri-state logic but the sd card doesn’t have many info, can the miso line on the sd card module be giving some problems?
i just need an assumption of what it could be.
I’d appreciate your help.
(image below)