boot animation not changing my

[AC Question]

Sir I have oppo r5 and ive tried changing boot animation by boot animation apk , rom toolbox apk, etc. I ve also tried to change it manually via root explorer. I found my original boot animation is in system/ media/ bootanimation. Whenever I put my animation in that and reboot my phone it shows so so small shining screen in very small pixel into a black screen what is the reason