This is a simple steganography challenge, this was easily solved by running the standard stego tools.

We are given a PNG image of a tractor.

Nothing visually stands out in the image so we can run strings on it. We can then use grep to search for the flag as we know that the flag format is pactf{...}.

strings trailer.jpg | grep pactf

We get nothing, is there a file hidden inside the image?

binwalk -e trailer.jpg
DECIMAL       HEXADECIMAL     DESCRIPTION
--------------------------------------------------------------------------------
0             0x0             JPEG image data, JFIF standard 1.01
30            0x1E            TIFF image data, big-endian, offset of first image directory: 8
16915         0x4213          PNG image, 960 x 640, 8-bit/color RGB, non-interlaced
17042         0x4292          Zlib compressed data, compressed

It has found an image, this can also be done with foremost.

foremost trailer.jpg
Processing: trailer.jpg
|*|

If we open the extracted image, we can see the flag.

Flag: pactf{tr41lEr.p4rk}