Optimal control of 1 producer 2 consumer with maximum buffer size problem

I'm trying to code a multithreading application to feed images to my machine learning models. Initially I had only one consumer thread (image processing) per each producer thread (in charge of doing image acquisition and feeding them to the buffer if there is empty space). Now I need two consumers to get all the images in the buffer.

For the single producer-consumer I used one mutex and two semaphores to make sure the buffer doesn't go above the maximum size I've established. The code is something like this:

sem_init(&waitPop, 0, bufferLimitSize) //wait pop is used to limit size of buffer
sem_init(&waitPush, 0, 0) //wait push is used to avoid trying to load from an empty buffer
    
void *producer(){
    while(thereAreImages){
        
        image = loadimage()
        sem_wait(&waitPop)
        mutex.lock()
        
//This part may be unnecesary or not well coded but adds more safety on limiting buffer size 
        if(buffer.size>=bufferLimitSize){
            mutex.unlock()
            mutex.lock()
        }

        buffer.push_front(image)
        mutex.unlock()
        sem_post(waitPush)
    }
}

void *consumer(){
    while(thereAreImages || !buffer.empty()){
        
        sem_wait(&waitPush)
        mutex.lock()

        data = buffer.back()
        image = data.clone()

        buffer.pop_back()

        mutex.unlock()

        sem_post(waitPop)

        doImageProcessing(image)
    }
}

This worked fine for me and I've tested it a lot but now I need one more consumer thread processing all the images that go to the buffer. Basically, I need both consumers to process the same images even though their processing times are not the same. I've been wondering for some days how could I manage that using as little resources as possible and I haven't found a way that doesn't make the buffer size bigger than desired.

To summarize, I need both consumers to clone every single image that goes into the buffer while avoiding feeding to the buffer more images than the buffer limit established and trying to access to the buffer when is empty.

Thanks in advance!