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*NOTE: Below instruction is for the theme version prior to v2.0.0. If you are using the theme v2.0.0 and above, you can just upload the image and it will be automatically scaled down to fit the area without hard cropping anymore. It means that the height of the slider will now be flexible depending on the uploaded image's proportion.
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Please try the followings:
1. Open "/includes/theme-functions.php" file then find this code:
add_image_size( 'theme-home-slider-image', 1170, 600, true );
Change from "600" to your new height number.
2. Open "style.css" file and find this CSS:
#home-slider-container {
background: url('images/loading.gif') no-repeat center;
min-height: 600px; /* init height */
margin: 35px 0;
overflow: hidden;
position: relative;
}
Again, change "600" to the new height number.
3. Re-upload the featured images for your slider. This makes WordPress to recreate the image and use the adjusted height in step 1.