How to quickly change wallpaper in c++?

Question

Is there any quick way to change a windows wallpaper in C++? I'm trying to animate a wallpaper and am going through a directory of images and setting the wallpaper to an image every few milliseconds, problem is, even when running on a thread, there is sometimes a time gap of a few seconds between wallpaper changes? How do I fix this? Am I doing something wrong? Here's my code:

#include <windows.h>
#include <string>
#include <iostream>
#include <chrono>
#include <thread>
#include <cstdlib>
#include <filesystem>

namespace fs = std::filesystem;
using namespace std;

void thinggg()
{
    cout << "Directory(0) or Files(1)?\n";
    int choice;
    cin >> choice;
    int num = 0;
    string* images;

    if (choice == 1)
    {
        cout << "How many images?\n";
        cin >> num;
        cin.ignore();
        images = new string[num];
        for (int i = 0; i < num; i++)
        {
            string loc;
            cout << i + 1 << ": ";
            getline(cin, loc);
            images[i] = loc;
        }
    }
    else
    {
        cin.ignore();

        string loc;
        cout << "Enter folder location: ";
        getline(cin, loc);

        // there is probably a much better to do this
        for (const auto& entry : fs::directory_iterator(loc))
        {
            num++;
        }
        images = new string[num];
        num = 0;
        for (const auto& entry : fs::directory_iterator(loc))
        {
            string path = entry.path().string();
            if (path.find("png") != string::npos || path.find("jpg") != string::npos || path.find("bmp") != string::npos)
            {
                images[num] = path;
            }
            num++;
        }
    }

    int intervals;
    cout << "Enter FPS: ";
    cin >> intervals;
    cin.ignore();
    intervals = 1000 / intervals;

    int i = 0;
    while (true)
    {
        wstring loc = wstring(images[i].begin(), images[i].end());
        const wchar_t* a = loc.c_str();
        SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, (void*)a, SPIF_SENDCHANGE);
        i++;
        if (i == num) i = 0;
        this_thread::sleep_for(chrono::milliseconds(intervals));
    }
}

int main()
{
    thread t(thinggg);
    t.join();
    cout << "quit?" << endl;
    int a;
    cin >> a;
    if (a == 1)
    {
        t.native_handle();
        return 0;
    }
}