Simple usage example of gif-h library - c++

Question

I'm attempting to create a minimal usage example for https://github.com/ginsweater/gif-h
But, starting with a vector<uint8_t> of size imageWidth*imageHeight, the second GifWriteFrame call throws an access violation reading location exception
My attempt:
#include <gif.h>
#include "BOBImageConversion.h"
int main(void)
{
// USAGE:
// Create a GifWriter struct. Pass it to GifBegin() to initialize and write the header.
// Pass subsequent frames to GifWriteFrame().
// Finally, call GifEnd() to close the file handle and free memory.
int delay = 100;
auto i1 = BOBImageIO::BOBLoadImage("Camera7.png");
auto i2 = BOBImageIO::BOBLoadImage("Camera18.png");
vector<uint8_t> vi1 = BOBImageConversion::ARGB2RGBAuint8(i1);
vector<uint8_t> vi2 = BOBImageConversion::ARGB2RGBAuint8(i2);
cout << (vi1.size() == i1.Width()*i1.Height()) << endl; // true
cout << (vi2.size() == i2.Width()*i2.Height()) << endl; // true
auto fileName = "gif.gif";
GifWriter g;
GifBegin(&g, fileName, i1.Width(), i1.Height(), delay);
GifWriteFrame(&g, vi1.data(), i1.Width(), i1.Height(), delay);
GifWriteFrame(&g, vi2.data(), i2.Width(), i2.Height(), delay); // Exception thrown: Access violation reading location
GifEnd(&g);
return 0;
}
For the above point the code posted is a minimal example. What's wrong?

Answer 1

This works
#include <vector>
#include <cstdint>
#include <gif.h>
int main()
{
int width = 100;
int height = 200;
std::vector<uint8_t> vi1(width * height * 4, 0);
std::vector<uint8_t> vi2(width * height * 4, 255);
auto fileName = "bwgif.gif";
int delay = 100;
GifWriter g;
GifBegin(&g, fileName, width, height, delay);
GifWriteFrame(&g, vi1.data(), width, height, delay);
GifWriteFrame(&g, vi2.data(), width, height, delay);
GifEnd(&g);
return 0;
}