Fix memcpy/sizeof typo in avifImageCopy

src/avif.c

diff --git a/src/avif.c b/src/avif.c
index 470174d..91499f8 100644
--- a/src/avif.c
+++ b/src/avif.c
@@ -149,7 +149,7 @@
     memcpy(&dstImage->pasp, &srcImage->pasp, sizeof(dstImage->pasp));
     memcpy(&dstImage->clap, &srcImage->clap, sizeof(dstImage->clap));
     memcpy(&dstImage->irot, &srcImage->irot, sizeof(dstImage->irot));
-    memcpy(&dstImage->imir, &srcImage->imir, sizeof(dstImage->pasp));
+    memcpy(&dstImage->imir, &srcImage->imir, sizeof(dstImage->imir));
 
     avifImageSetProfileICC(dstImage, srcImage->icc.data, srcImage->icc.size);