我使用 VC++、boost::gil 包和 lpng 包来读取 png 图像。调试后我有以下链接问题：
Error 3 error LNK2001: unresolved external symbol _png_set_swap img_seq_interp.obj img_seq_interp
Error 4 error LNK2001: unresolved external symbol _png_get_bit_depth img_seq_interp.obj img_seq_interp
Error 5 error LNK2001: unresolved external symbol _png_read_info img_seq_interp.obj img_seq_interp
Error 6 error LNK2001: unresolved external symbol _png_set_sig_bytes img_seq_interp.obj img_seq_interp
Error 7 error LNK2001: unresolved external symbol _png_init_io img_seq_interp.obj img_seq_interp
Error 8 error LNK2001: unresolved external symbol _png_set_longjmp_fn img_seq_interp.obj img_seq_interp
Error 9 error LNK2001: unresolved external symbol _png_destroy_read_struct img_seq_interp.obj img_seq_interp
Error 10 error LNK2001: unresolved external symbol _png_create_info_struct img_seq_interp.obj img_seq_interp
Error 11 error LNK2001: unresolved external symbol _png_create_read_struct img_seq_interp.obj img_seq_interp
Error 12 error LNK2001: unresolved external symbol _png_sig_cmp img_seq_interp.obj img_seq_interp
Error 13 error LNK2001: unresolved external symbol _png_get_image_width img_seq_interp.obj img_seq_interp
Error 14 error LNK2001: unresolved external symbol _png_get_image_height img_seq_interp.obj img_seq_interp
Error 15 error LNK2001: unresolved external symbol _png_read_end img_seq_interp.obj img_seq_interp
Error 16 error LNK2001: unresolved external symbol _png_read_row img_seq_interp.obj img_seq_interp
Error 17 error LNK2001: unresolved external symbol _png_get_IHDR img_seq_interp.obj img_seq_interp
Error 18 fatal error LNK1120: 15 unresolved externals C:\Studium\codes\vc++\img_seq_interp\Debug\img_seq_interp.exe img_seq_interp
它是怎么来的？我需要一些库来链接问题吗？