you can do this way :

<input id="takePic" className={classes.takePic} type="file" accept="image/*" />

<Button className={classes.addImage} onClick={this.handleClick}>


 handleClick=()=>{
   document.getElementById('takePic').click();
}

you can do this way :

<input id="takePic" className={classes.takePic} type="file" accept="image/*" />

<Button className={classes.addImage} onClick={this.handleClick}>


 handleClick=()=>{
   document.getElementById('takePic').click();
}

read more here : https://www.w3schools.com/jsref/met_html_click.asp