Image displayed using Flask is wrong or corrupt-PHP Chinese Network Q&A

I'm setting up a web application in which I need to display some images. The images I receive from the API convert the matplotlib plot to png and then send it to the main web application using the io library. Because of this, the images I display on the page almost always appear incorrect or wrong. But if I open them in a new page via context menu, they work fine.

So this code for sending pictures

@app.route('/send-data-a', methods=['GET'])
def send_data_user_dynamic():
...some code for diagram...
image_stream1 = io.BytesIO()
        plt.savefig(image_stream1, format='png')
        image_stream1.seek(0)
        plt.close(fig)

        return send_file(image_stream1, mimetype='image/png')

I tried putting the timestamp in the main app so the links would be unique but that didn't help

@app.route('/data', methods=['GET'])
def data():
    timestamp = int(time.time())

    user_dynamic = requests.get(f'http://127.0.0.1:5000/send-data-a?timestamp={timestamp}')
    user_amount = requests.get(f'http://127.0.0.1:5000/send-data-b?timestamp={timestamp}')
    kp_month = requests.get(f'http://127.0.0.1:5000/send-data-c?timestamp={timestamp}')
    kp_week = requests.get(f'http://127.0.0.1:5000/send-data-d?timestamp={timestamp}')

    return render_template('second.html',
                           user_dynamic=user_dynamic.url,
                           user_amount=user_amount.url,
                           kp_month=kp_month.url,
                           kp_week=kp_week.url)
if __name__ == '__main__':
    app.run(debug=True, port=5001)

And there is an html template to output them

<div class="diagram">
        <img src="{{ user_dynamic }}" alt="user_dynamic">
        <figcaption>some text</figcaption>
    </div>

import base64 user_dynamic_response = requests.get('http://127.0.0.1:5000/send-data-a') user_amount_response = requests.get('http://127.0.0.1:5000/send-data-b') kp_month_response = requests.get('http://127.0.0.1:5000/send-data-c') kp_week_response = requests.get('http://127.0.0.1:5000/send-data-d') user_dynamic_image_data = base64.b64encode(user_dynamic_response.content).decode('utf-8') user_amount_image_data = base64.b64encode(user_amount_response.content).decode('utf-8') kp_month_image_data = base64.b64encode(kp_month_response.content).decode('utf-8') kp_week_image_data = base64.b64encode(kp_week_response.content).decode('utf-8') return render_template('second.html', user_dynamic=user_dynamic_image_data, user_amount=user_amount_image_data, kp_month=kp_month_image_data, kp_week=kp_week_image_data)