How to download image?

Using Streamlit
1

I demo this repo , and I wanna set a button to download a Processed image. .

I try cv2.imwrite(‘messigray.png’,img) but not work.

2

Hi @sevaroy, welcome to the Streamlit community!

This thread shows several examples of how to create a download link. In your code snippet, you are writing the image to a folder somewhere. So you either need to be able to pass that file location to a button for people to click, or you need to pass the actual bytes of the file to your download link.

3

Thank you! This works for me.

1 Like
4

Use the following function to download the image file, you can same code for every file, just you need to change the extension and saving technique according to a different file.

This function will create the link for downloading the Image file

def get_image_download_link(img,filename,text):
    buffered = BytesIO()
    img.save(buffered, format="JPEG")
    img_str = base64.b64encode(buffered.getvalue()).decode()
    href =  f'<a href="data:file/txt;base64,{img_str}" download="{filename}">{text}</a>'
    return href

Function Call

## Original image came from cv2 format, fromarray convert into PIL format
result = Image.fromarray(original_image)
st.markdown(get_image_download_link(result,img_file.name,'Download '+img_file.name), unsafe_allow_html=True)
5

Hey all :wave:,

We now have Download Button natively supported in Streamlit via the 0.88.0 release with st.download_button!

To use, upgrade to the latest version:
pip install --upgrade streamlit

Check out these helpful links:

@sevaroy @Spidy20

2 Likes
6

Hello @randyzwitch. Would you have any suggestions on how to download a 3D tiff image? (Here the third dimension may have a size of more than 3, so it is not necessarily an RGB image).

I mentioned this question here as well for completion.

7

Hello Jessica sorry to hijack the discussion I was wonder possible you can point me out to solved this issue.

st.write("Preview")
#openCV image result cropped_image which is an np array
st.image(cropped_image)
#cropped_image converted to PIL image color      
result = Image.fromarray(cropped_image.astype('uint8'), 'RGB')
    
img = Image.open(result)            

btn = st.download_button(
      label="Download image",
      data=img,
      file_name="imagename.png",
      mime="image/png")

I want to use st.download_button to download the image result I know I cannot no use the cropped_image result since it is a np array. I converted the image array to a PIL image but I don’t know how I can from here get the result image filename. Could you please give me some ideas how to solve this issue.

8

hi, i have the same issue. how did you solved?

9

In case someone needs a solution, what I did was to convert the img (in my case it was numpy array) to io.BufferedReader.

im_rgb = im_bgr[:, :, [2, 1, 0]] #numpy.ndarray
ret, img_enco = cv2.imencode(".png", im_rgb)  #numpy.ndarray
srt_enco = img_enco.tostring()  #bytes
img_BytesIO = BytesIO(srt_enco) #_io.BytesIO
img_BufferedReader = BufferedReader(img_BytesIO) #_io.BufferedReader

cols_srcnn[i].download_button(
label="Download",
data=img_BufferedReader,
file_name="srcnn_img_"+str(i)+".png",
mime="image/png"
)
10 
from io import BytesIO
buf = BytesIO()
img.save(buf, format="JPEG")
byte_im = buf.getvalue()

Now you can use the st.download_button

btn = col.download_button(
      label="Download Image",
      data=byte_im,
      file_name="imagename.png",
      mime="image/jpeg",
      )
1 Like
11

Hello.

I am developing an App that from a library generates an image but it is not being saved as a png or jpg file, it is just being displayed but I need that the person using the app can download it through a button of some kind. Is this possible?
This is what the image looks like:

image
image1366×768 124 KB

12

What library do you use? Can you show your code that generates the image?

13

Hii Javier_Jaramilo
this code is working good but the 3rd “img.save(buf, format=“JPEG”)” is not working
this is showing me error :- NameError: name ‘img’ is not defined

please help me

14

hiii
you can use this code to download the image
from io import BytesIO
buf = BytesIO()
img.save(buf, format=“JPEG”)
byte_im = buf.getvalue()
btn = st.download_button(
label=“Download Image”,
data=byte_im,
file_name=“graph.jpg”,
mime=“image/jpg”,
)
but this line code " img.save(buf, format=“JPEG”)" is not working

15

what dose the first two show ?
t

16

Hey Pawan, sorry I was a little late. Well maybe the reason img.save(buf, format=“JPEG”)" won’t work it is becuase thats you image.
So for example:
img = “path/example.jpg” # or any other format and them when you have the image in the buffer the rest of the code get execute.
Or in other work you need to have you image in the buffer first to further processing.