Try these curated collections

A  truck with the national flag of USA depicted on the back door carries goods to another country along the highway. Concept of export-import,transportation, national delivery of goods
open trailer
Back of Delivery or Moving Truck
realistic truck. back view.
White steel door of car truck container
Box truck or box van back view isolated on white background,
Cargo box or steel box for storage and transport cargo and high volume of goods product, clipping path include in file.
Van car open door, back view. 3D rendering
Rear view of new white cargo truck
Van car commercial trailer, back view. 3D rendering
Back of trailer truck icon vector in trendy flat style isolated on white background
open truck trailer
Truck of logistic. Back of delivery van. Open and closed door of container with boxes. Cargo in truck for transportation and export. Car for delivery of good from warehouse. Cartoon lorry rear. Vector
Empty van with open doors an light inside Empty van
Light truck (Set #14)  in vector . 

Optimized approximately to 166 x 90
Box truck or box van back view isolated on white background,
Cargo box or steel box for storage and transport cargo and high volume of goods product, Small cargo container delivery service.
Empty yellow moving truck with blue dolly in back.
The open rear doors of a lorry
Two New Box Delivery or Moving Trucks
Back doors of new white cargo truck isolated on white
Generic American red semi truck with semi trailer with opened back doors from the back right view, photo realistic isolated 3D illustration on the white background.
Closed rear doors of parked shipping truck with blank license plate
Truck for transportation cargo. Vector illustration. Isolated on yellow background. Cartoon truck. White truck. Delivery of cargo
white open truck
realistic trucks set. front view; side view; back view.
Closed back doors at delivery truck
Moving Truck with Boxes. Back side of the loading truck. Cardboard boxes inside and outside the vehicle.Packed interior furniture and cat. lettering moving home qoute.Vector cartoon style illustration
Box truck or box van back view isolated on white background,
Cargo box or steel box for storage and transport cargo and high volume of goods product, Small cargo container delivery service.
The convoy of semi trucks with reefer trailers on flat like an arrow evening road with lights on and reflection of light on a shiny trailer stainless steel doors. Trucks driving on a divided highway
white truck on rural highway with dramatic clouds, rear view, slightly blurred in motion
View of truck back with the image of boiled potatoes on the doors
white truck
Truck's back door locked with a key
Back view of cargo container on back trailer,  Cargo container or shipping container for shipment storage and transport goods product and raw material, Vector illustration design variety color.
Security door of shipping container, road freight cargo transport.
Transport truck waiting for loading export merchandise at industrial warehouse, transportation or logistic concept .
Open delivery truck with cardboard boxes and closed truck. Isolated on blue background. Back view. Transport services, logistics and freight of goods. Flat style, vector illustration.
realistic cargo van. front view; side view; back view.
realistic truck. back view.
Blank space on back of truck perfect for your advertisement
Back view of cargo container on back trailer,  Cargo container or shipping container for shipment storage and transport goods product and raw material, Vector illustration design.
Driver opens the door on trailer of parked truck. Lorry parked in the countryside. Beautiful landscape at background.Back view Slow motion Close up.
Generic urban delivery refrigerator box truck with grey cabin, back right view with opened doors, photorealistic 3D Illustration, isolated on the white background.
Open delivery truck with cardboard boxes. Isolated on blue background. Transport services, logistics and freight of goods. Flat style, vector illustration.
Safety lock on the back of truck, transport and vehicle
Warehouse building with 53 foot dry van trailers backed into docking doors
The image of back part of a van
Back view of an empty cartoon truck with door open and closed
realistic truck. front view; side view; back view.
loading dock
realistic truck. front view; side view; back view.
Delivery truck. Doors can be opened, colors can be changed, the elements are in the separate layers. I'd recommend to rasterize each vector layer before exporting the file to PSD format.
Truck (Set #11) in vector.
Truck trailer rear view icon. White background with shadow design. Vector illustration.
Container door Taken in the container
Commodity shipping truck back door with a lock.
Truck (Set #12) in vector.

The  size is optimized approximately to 200 x 90 pixels (side view)
Cargo container on back trailer and towed by front tractor,  Cargo container or shipping container for shipment storage and transport goods product and raw material, Vector illustration design.

Search for "truck back door" in these categories

Closeup of black shipping storage container pad locks.
Delivery van.  Doors can be opened, colors can be changed, the elements are in the separate layers. I'd recommend to rasterize each vector layer before exporting the file to PSD format.
Door of truck
Cargo Express Van Vehicle back view. 3D rendering
Seattle, Washington March 6th 2018: The Paramount theater showing the Broadway musical Hamilton view of art on the travel trailer with back door.
Vector illustration of truck loaded with boxes with bar-codes back view
Closed doors of cargo truck, handle and lock of delivery vehicle with white bodywork, commercial transport industry, detail
A  truck with the national flag of Canada depicted on the back door carries goods to another country along the highway. Concept of export-import,transportation, national delivery of goods
Delivery truck door and transportation car concept - Close up back door of delivery truck parking for delivery a parcel to receiver and copyspace
lorry under the white background
realistic truck. front view; side view; back view.
small truck with red cab stands with open empty body ready for loading cargo. ?lipping path is included
Cargo container or shipping container with strength for shipment storage and transport goods product and raw material between location or country, International trade equipment to exchange goods.
Empty truck and trailer with open back door
Cargo container on back trailer and towed by front tractor,  Cargo container or shipping container for shipment storage and transport goods product and raw material, Vector illustration design.
Generic American white semi trailer with opened back doors from the back view, photo realistic isolated 3D illustration on the white background.
Truck for transportation cargo
Open back door of delivery truck parked outside store
Truck trailer rear view side with closed and open doors. Delivery van isolated. Express delivering services commercial truck. Fast and free delivery by car. Cargo logistic. Flat vector illustration
behind the transportation truck
Row back side of new trucks
Truck trailer rear view icon on gray background, round shadow. Vector illustration.
Viersen - Dülken, Nordrhein Westfalen, Germany -  December, 30, 2020:  An ambulance is waiting for a patient. The back door is open. Stretcher patient transport. Back view.
Cargo truck with trailer four angle set. Truck side, back and front view. Vector flat style illustration.
Row back and face side of new trucks
Red shipping container cargo background, close up of container back door locked
white door of container  background
Delivery refrigerated truck.  Doors can be opened, colors can be changed, the elements are in the separate layers. I'd recommend to rasterize each vector layer before exporting the file to PSD format.
Shipping metal container on white isolate background.
Truck trailer rear view icon. Flat design. Vector illustration.
Blue metal containers
van under the white background
Generic urban delivery refrigerator box truck with grey cabin, back view with closed doors, photorealistic 3D Illustration, isolated on the white background.
backdoor of delivery or moving truck
Close up lock of Cargo Truck
Close up Handle and lock of Cargo Truck
Row back side of new trucks
Face of new black truck
Three New Box Delivery or Moving Trucks
Row back and face side of new trucks
back door of white van open with isolated white background
Retro pickup truck and van (1930-40th). Car icons in vector. The shadows are in the separate layer.
View of the entire rear of the school bus isolated on the white background
of 25